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Glossary

A

  • AGS

    The American Gem Society (AGS) is a trade association of retail jewellers, independent appraisers, suppliers, and selective industry members, founded in 1934 by Robert M. Shipley, who also founded the GIA. Members are held to a high code of ethics with emphasis on consumer protection and education.
    The Society trains and certifies jewellers, gemmologists, and jewellery appraisers and has developed its own cut, colour, and clarity standards.

  • ALLOY

    An alloy is a mixture or metallic solid composed of two or more elements e.g. a copper and gold alloy in varying ratios produces Rose Gold with its distinct colour.

  • ALLUVIAL STONE

    An alluvial stone is one which has been transported by water and deposited in seas, lakes or stream beds. Many gemstones, including diamonds, are found in alluvial deposits.

  • AMERICAN CUT

    The American Cut follows the proportions and facet angles calculated mathematically by Marcel Tolkowsky and is considered by many to constitute the ideal cut.

  • ANGLES

    In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle. In diamond cutting the term refers to the angle at which the stone is cut to form the shape of its cut and maximise its brilliance.

  • ANTWERP DIAMOND BOURSE

    Antwerp has been home to a flourishing diamond industry for the past 500 years. Today, it has become the world's most important diamond centre, importing over 80% of the world's rough and polished diamonds before being distributed further.The Antwerp diamond Centre, or Bourse is located in the centre of Antwerp, collectively trading billions of dollars’ worth of diamonds annually. Their activities are based on tradition, following strict rules established over the past five centuries.

  • APPRAISAL

    An appraisal is the decision method applied to the grading and certification of a diamond, precious metal or other gemstone. A gemmologist or jeweller will examine the piece in question and give a formal or informal professional opinion on the grading and criteria of the diamond or jewellery piece.

  • ASSCHER CUT

    In 1902 Joseph Asscher upheld his father's reputation for skill and innovation by designing the original Asscher cut. This emblematic cut was the first signature cut to be patented. The Asscher Diamond Company held its exclusive patent until the Second World War and saw strong sales internationally.

B

  • BAGUETTE

    The baguette cut in which the lustre of a stone is accentuated using a linear cut moderating the appearance of its fire came to the fore during the Art Deco period. Today, it is often used in period and ‘vintage style’ pieces.

  • BAIL

    A bail is a component of certain types of jewellery, mostly necklaces, used to attach a pendant. The bail is normally placed in the centre of the necklace where the pendant hangs.

  • BAND

    A circular band worn as a type of ornamental jewellery around a finger; it is the most common current meaning of the word ring. Other types of metal bands worn as ornaments are also called rings, such as arm rings, often more commonly called bangles or torques and neck rings, also called a torque or a collar.

  • BANGLE

    Bangles are circular in shape, and, unlike bracelets, are not flexible. The word is derived from Hindi bungri meaning glass. They are made of numerous precious as well as non-precious materials such as gold, silver, platinum, glass, wood, ferrous metals, plastic, etc. Bangles are part of traditional Indian jewellery. Designs range from simple bands of silver, or gold to intricate hand wrought designs, often studded with precious and semi-precious stones such as diamonds, gems and pearls.

  • BAR SETTING

    In a bar setting, individual metal bars are set perpendicular to the ring, separating the gemstones. The metal is then moulded around a gem to lock it in place.

  • BARREL CLASP

    Barrel clasps are a type of fastener seen on pieces of jewellery, such as necklaces or bracelets. Each end of a barrel clasp is attached to one end of a chain, rope, thread, or other material and fits together to complete a connection, securing the jewellery. Barrel clasps either screw together on tiny threads or they lock together using magnets.

  • BEAD SETTING

    Bead setting is a generic term for setting a stone directly into metal using gravers, also called burins, which are essentially tiny chisels. A hole is drilled directly into the metal surface, and then a ball burr is used to make a depression to fit the exact size of the stone.

  • BEARDED GIRDLE

    The edge or girdle is the weakest part of the Diamond being thin and vulnerable. A strike to the stone at the wrong angle can chip a section of the girdle away. A hard strike can fracture a diamond, turning it into pieces of cloudy sections. Diamonds, particularly older diamonds which may have been worn often have multiple small fractures around the whole, or portions of the girdle, termed "Bearded Girdles"

  • BEZEL

    The Bezel setting is the earliest technique of attaching stones to jewellery. A bezel is a strip of metal bent into the shape and size of the stone and then soldered to surround the gem within the piece of jewellery. Then the stone is inserted into the bezel and the metal rubbed over the stone, holding it in place. This method is more often used for cabochon or faceted stones.

  • BEZEL FACETS

    The facet located on the crown, or top portion, of a diamond. Jewellers call this the 'kite' facet because of its shape.

  • BLACK DIAMOND

    When a diamond is dark grey, a very dark green or truly black, it is referred to in the trade as a "black diamond." Such a stone may be opaque to nearly semi-transparent.

  • BLEMISH

    Any surface imperfection on a fashioned diamond; e.g., a nick, knot, scratch, abrasion, minor crack or cavity, or poor polish is described as a blemish. Also, a natural or an extra facet, visible on or through the crown, is usually considered a blemish.

  • BLOOD DIAMONDS

    In relation to diamond trading, the term ‘Blood Diamond’ refers to a conflict diamond, (also called a converted diamond, blood diamond, hot diamond, or a war diamond) mined in a war zone and sold to finance illegal or unethical activity, e.g. an insurgency, invasion, war efforts, or the unsanctioned activity of an individual. Usually originating from troubled areas in Africa where around two-thirds of the world's diamonds are extracted.

  • BLUE BOOK

    The CIBJO's operations include the development of the Blue Book, a three-part publication outlining terminology, classification, and ethical guidelines (i.e., disclosure of treatments and synthetics) for coloured gemstones, diamonds, and pearls.

  • BLUE DIAMOND

    A diamond with a distinctly blue body colour is a fancy diamond. Diamonds that are blue in both daylight and incandescent light are rare, although fluorescent stones which exhibit a blue colour in daylight are comparatively common. A blue colour may also be induced artificially.

  • BLUEGROUND

    Blueground is the diamond miner's nickname for "Kimberlite," the rock which contains diamonds in the South African pipe mines.

  • BLUE WHITE

    Blue-white refers to the fluorescence in diamonds which may occur in natural light. This blue fluorescence occurs to differing degrees and may make a colourless diamond appear oily or milky in sunlight, decreasing its value. For stones with a faint yellow colour, toward the lower end of the colour scale, a moderate amount of fluorescence can make it appear whiter as the fluorescence will negate some of the yellow.

  • BODY COLOUR

    The colour of a diamond as observed when examined under a diffused light against a colour-free background away from surrounding reflections. The use of diffused light eliminates glaring reflections and dispersion, which may otherwise confuse the colour determination.

  • BOMBARDED DIAMOND

    A ‘bombarded’ diamond is one which has been subjected to the artificial process of bombardment by fast electrons; to make the colour of the stone more attractive and desirable.

  • BORT

    Bort or boart is a term used in the diamond industry to refer to shards of gem-grade/quality diamonds. In the manufacturing and heavy industries, "bort" is used to describe dark, imperfectly formed/crystallized diamonds of varying levels of opacity. The lowest grade, "crushing bort", is used to make industrial-grade abrasive grits. Small bort crystals are those used in diamond drill bits. The Democratic Republic of the Congo provides 75% of the world supply of crushing bort.

  • BOURSE

    A French word, meaning an exchange or meeting place where merchants transact particular business. The word is often used for a diamond dealers club or organization e.g. Antwerp Diamond Bourse.

  • BOW TIE EFFECT

    A specific effect caused by an area of shadow visible in some fancy shapes, caused by poor cutting, allowing light to ‘leak’ from the bottom of the diamond.

  • BOX CHAIN

    A box chain is made up of square links, individually resembling a box, connected to create a smooth chain.

  • BOX CLASP

    A popular clasp for multi-strand bracelets necklaces, particularly pearls consisting of a box, tongue, snag, and trigger. Although there are several variations to the clasp, all of them work on the same principal.

  • BREAK FACETS OR GIRDLE FACETS

    The 32 triangular facets adjoining the girdle of a round brilliant-cut stone, featuring 16 above the girdle and 16 below the girdle.

  • BRIDAL SET

    A traditional set Bridal Set consists of two rings which match and/or fit together- the engagement ring and the wedding band. A Trio Set is three rings in a matched set, an engagement and wedding band for the bride and coordinating wedding band for the groom.

  • BRILLIANCE

    The term brilliance refers to the amount of light returned to the eye from the interior of a gem and is mainly a function of refractive index, proportions and transparency. The amount of brilliance, or ‘fire’ exhibited in a stone is dependent on the grade of cut.

  • BRILLIANT CUT

    The last part of cutting and polishing the diamond; the brillianteer adds twenty-four facets to the crown and sixteen facets to the pavilion.

  • BRILLIANTEERING

    The last part of cutting and polishing the diamond; the brillianteer adds twenty-four facets (usually triangular) to the crown and sixteen facets to the pavilion.

  • BRIOLETTE

    Describes a shape and a style of faceting (cutting) .Briolettes are usually an oval or pear shape drop bead with its entire surface cut in angular facets.

  • BROKER

    A broker is a third party who arranges a transaction between a buyer and a seller, usually earning commission when the deal is completed. A broker who also acts as a seller or as a buyer becomes a principal party to the deal.

  • BROWN DIAMOND

    Often described as ‘champagne’, ‘coffee’ or ‘cognac’ diamonds, fancy coloured brown diamonds are now entering an age of vogue as the trend for fancy coloured diamonds continues and demand increases.

  • BRUISE

    Often visible damage to a diamond consisting of surface crumbling, often accompanied by tiny, root like feathers

  • BRUSHED FINISH

    A brushed finish, also known as a ‘satin’ finish, is a texturing technique used with precious metals in jewellery where a series of tiny parallel lines are scratched on the surface with a fine wire brush.

  • BRUTING

    Bruting is the first step in cutting a diamond; involving the shaping of the girdle, giving the stone its basic shape.

  • BUBBLE

    Bubbles are spherical or tear-shaped bubbles of gas captured in glass stones. Bubbles can also be found in resins like amber, and less-frequently in minerals like Amethyst, Emerald, and Topaz

  • BURNED FACET

    A facet may appear whitish, or burnt, as a result of the cutter polishing the facet "against the grain", this is known as a burned facet.

  • BYZANTINE CHAIN

    A chain with close-fitting links, creating an intricate design that forms a tube.

C

  • CABLE CHAIN

    A cable chain consists of interconnected round links of the same size.

  • CABOCHON CUT

    The art of rounding a gem without facets into the shape of a highly-polished dome, the earliest type of gemstone shaping, the cabochon was once commonly seen in Star Sapphires and Rubies but is now emerging as a popular style in semi-precious stones.

  • CAIRO STAR

    The Cairo Star is a rarely used, blocky cut consisting of 74 facets of which there are two main variations. Developed from the Briolette cut, the Cairo Star is a style of brilliant cut used to retain maximum weight with a minimum loss of brilliancy.

  • CANARY DIAMOND

    Canary diamonds are golden yellow in colour with fluorescence occurring in yellow, golden and orange colours; also known as fancy yellow.

  • CAPE

    A broad range of diamond colour grades that show a distinct yellow tint face up (except for small stones in the top part of the range).

  • CARAT (CT)

    When the word ‘carat’ is applied to gemstones, including diamonds, it means a unit of weight. A carat is equal to 0.20 grams, one fifth of a metric gram. A measure, from 1 to 24, used to indicate how much of a piece of jewellery is gold content and how much an alloy.

  • CARAT TOTAL WEIGHT (CT.TW)

    The total amount of the carats in a piece of jewellery. A carat is the equivalent of 0.2 metric grams.

  • CARBON

    Carbon (Ca) is the element of which all diamonds are formed.

  • CARBONADO

    Carbonado is imperfectly crystallised diamond, usually black or grey, it is usually ground or crushed to be used as an abrasive or for other industrial diamond use.

  • CARBON PINPOINTS

    Carbon pinpoints are miniscule inclusions visible as interior spots in a Diamond. A cluster of pinpoints can form a cloud.

  • CARBON SPOTS

    These are small, dark-appearing diamond inclusions that, upon close inspection, are usually seen to be clear diamond crystals, clear mineral crystals or cleavages.

  • CATHEDRAL SETTING

    A cathedral setting has a split band forming an upper and lower segment with a distinctive arch between them. The lower ring band encircles the finger, while the upper portion of the band arches up to embrace the central mounting and focal diamond or gemstone, which is frequently in a classic tiffany (six prong) setting.

  • CAVITY

    A cavity is a type of inclusion consisting of a relatively wide or deep opening in a diamond.

  • CENTENARY

    The De Beers Centenary Diamond is, at 273.85 carats the third-largest diamond to have been produced in the Premier Mine. The Centenary Diamond is rated as grade D colour and is internally and externally flawless. It was named the Centenary Diamond as it was presented in the rough for the Centennial Celebration of De Beers Consolidated Mines on May 11, 1988. The Centenary Diamond was unveiled in its final form in May 1991.

  • CENTRE STONE

    The central, dominant stone in a piece of jewellery set with multiple stones.

  • CERTIFICATES, CERTIFICATION

    Certificates, more accurately known as diamond grading reports, are commonly provided with the purchase of a significant piece of diamond jewellery such as a diamond Engagement Ring. Certification may be purchased by a retailer from a gemmological institute or in the case of larger jewellery houses and independent gemmologists, is provided in-house, matched against their own, often more specific criteria.

  • CERTIFIED

    Diamonds can be purchased with certificates from bodies including the IGI and the GIA. Larger more established jewellery houses, gemmologists and diamond merchants will provide their own certification and valuation certificates.

  • CERTIFIED GEMMOLOGIST

    A title awarded by the American Gem Society. To qualify, a person must study coloured stones and their identification alongside and diamond grading and appraising.

  • CHAIN

    In jewellery, chains involve a number of connected loops, links, rings, or beads ordered one after the other.

  • CHAMPAGNE DIAMOND

    A trade term describing a light yellow diamond with green or brown overtone lacking the intensity of colour to be classified as a ‘Fancy’ colour Diamond.

  • CHANNEL SETTING

    Channel setting is a technique whereby gemstones are set side-by-side with their girdles held between two tracks of precious metal.

  • CHEMICAL VAPOUR DEPOSITION

    Chemical vapour deposition (CVD) is a chemical process used to produce high-purity, high-performance solid materials. The process is often used in the semiconductor industry to produce thin films.

  • CHIFFRE

    A three-faceted shield-shaped rose cut with a flat, un-faceted base.

  • CHIP

    A shallow break on a diamond which extends from a facet junction or girdle edge, classified as larger or deeper than a nick.

  • CHOKER

    A choker is a type of necklace that fits tightly around the neck. Chokers are from 14" to 16" in length.

  • CLARITY

    Clarity or ‘clearness’ is one of the four most important grading factors affecting the quality and value of a diamond.

  • CLARITY ENHANCED, CLARITY ENHANCEMENT

    A broad term for gemstones covering many different treatments or procedures which may remove or diminish the appearance of flaws, thereby enhancing the clarity.

  • CLASP

    A clasp is a fastener which can open and close, attaching two things together e.g. the two ends of a necklace, or bracelet.

  • CLAW SETTING

    A claw setting is one in which a series of metal prongs (claws) hold a stone securely in a setting with no metal directly under the stone.

  • CLEAN

    Clean is a frequently misused term to describe a diamond with slight imperfections. ‘Clean’ can also be used to describe a diamond with internal imperfections. Use is prohibited by the FTC unless the stone qualifies as "perfect" as described by the commission.

  • CLEAVAGE

    Cleavage refers to a gemstone's tendency to break parallel to certain flat planes. Cleavage is rarely entirely on one level or plane and can have a step-like appearance.

  • CLEAVAGE CRACK

    A break parallel to a cleavage plane; characterised by a two-dimensional nature; intersections with facets are usually straight lines.

  • CLOSED CULET

    A culet on a diamond that is too small to be resolved with the unaided eye and that can be seen only with difficulty under 10x magnification. The term is rarely used to refer to a pavilion point or ridge with no "culet."

  • CLOSED TABLE

    A term used by some to designate a small table diameter. However, its interpretation and use varies. It may refer to a diameter less than the American cut 53% (of the girdle diameter) or, more frequently, to a table smaller than about 60.

  • CLOUD

    A ‘cloud’ refers to a grouping of a number of tiny inclusions which are too small to be distinguishable from one another, even under magnification.

  • CLOUDY TEXTURE OR CLOUD TEXTURE

    A group of tiny white inclusions composed of minute hollow spaces, or very small patches of tiny crystals or other impurities that produce a cottony or clouded appearance in a n otherwise highly transparent diamond. A cloud may be so minute that it is difficult to see under 10x magnification, or it may be large enough to deprive the entire stone of brilliancy.

  • CLUSTER SETTING

    This setting surrounds larger centre stone with several smaller stones. It is designed to create a larger gemstone ring effect utilising many smaller stones.

  • COATED DIAMOND, COATING

    A diamond coloured by a surface coating which masks the true body-colour; the coating may be extensive (entire pavilion, for example), but is more often limited to one or two pavilion facets or a spot on the girdle.

  • COGNAC

    Cognac is a traditionally more desirable fancy brown colour than dark brown. Cognac exhibits an orange-brown colour similar to that of cognac.

  • COLLET, COLLETS

    Collet is a style of setting used to hold gemstones in place. It is also known as claw and consists of a 'Bezel' and 'Prong'.

  • COLORIMETER

    A colorimeter is a device used in the field of Colorimetry to measure the absorbance of particular wavelengths of light. In diamonds, a colorimeter is used in the lab to grade diamond colour, giving a scientific and subjective report which is then used alongside the eye grading of the gemmologist.

  • COLOUR

    When grading diamonds, 'colour' refers to the absence or presence of colour in a diamond. In ‘white’ diamonds, the rating scale begins at D (meaning entirely colourless) and ends at Z (meaning having a presence of colour, usually a yellow hue). Colour grading in ‘fancy coloured’ stones goes through the full colour spectrum from fancy yellow through varying degrees and combinations of blues, greens, reds, browns and black.

  • COLOUR GRADING

    The system of grading diamond colours based on their colourlessness (for white diamonds) or their spectral hue, depth of colour and purity of colour (for fancy colour diamonds). For white diamonds, HRD and IGI use a grading system which runs from D (totally colourless) to Z (light yellow).

  • COMFORT FIT

    The rounded finish on a ring's interior, designed to provide additional comfort for long-wear.

  • COMMERCIAL WHITE

    ‘Commercial white’ is a misleading term used to market near white, but slightly off-colour diamonds. Often misused, the AGS and the FTC prohibits use of this term.

  • COMMERCIALLY CLEAN

    The common meaning of this term is "reasonably free from inclusions." If a diamond is entirely without flaws or blemishes, it would be called flawless or perfect.

  • CORUNDUM

    Corundum is crystalline aluminium oxide, second hardest on Mohs Scale after diamond, and one of the most popular (and valuable) of gem minerals. Red corundum is known as Ruby; all other colours are known as Sapphire.

  • CRAFTSMANSHIP

    An artisan is a skilled craftsman who makes items including jewellery to a high standard.

  • CREATED

    An artificial gemstone made in a laboratory with the same properties as a genuine gemstone. Also known as synthetic stone, created gemstones are made to give the outward appearance of a gemstone without the same high cost.

  • CRITICAL ANGLE

    The critical angle is the greatest angle measured from normal at which light can be refracted out of a stone; a small angle at which light is totally internally reflected.

  • CROWN

    The term crown describes the top part of a facetted gemstone above the girdle.

  • CROWN ANGLE

    The angle at which a diamond’s bezel facets (or, on emerald cuts, the row of concentric facets) intersect the girdle plane.

  • CROWN HEIGHT

    The crown height expressed as a percentage of the average girdle diameter.

  • CRYSTAL

    Crystal is mostly glass mixed with lead - the magic ingredient that gives crystal its sparkle. Lead makes the glass heavier and allows the glass to be cut and given facets, making it glint and twinkle - like a diamond.

  • CRYSTAL STRUCTURE

    In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry. Patterns are located upon the points of a lattice, which is an array of points repeating periodically in three dimensions. The points can be thought of as forming identical tiny boxes, called unit cells, that fill the space of the lattice. The lengths of the edges of a unit cell and the angles between them are called the lattice parameters.

  • CUBE

    One of the seven basic forms in the highest symmetry (hexoctahedral) class of the cubic, or isometric, crystal system. It has six square faces that make 90° angles with one another, each of which intersects one crystallographic axis and is parallel to the other two. Gem-quality cube-shaped diamond crystals are so rare as to be regarded as collector's items.

  • CUBIC SYSTEM

    The Isometric crystal system which consists of three axes, each of equal length and perpendicular to others.

  • CUBIC ZIRCONIA

    The diamond substitute known as cubic zirconia was found naturally formed in the 1930's but today it is simulated in a laboratory environment, as natural forms are no longer easily found.

  • CULET

    The culet (pronounced cue-let) is the small area at the bottom of a diamond's pavilion. The culet can be a point or a very small facet sitting parallel to the table.

  • CULLINAN, CULLINAN I, CULLINAN II

    Cullinan Diamond is a pear shaped diamond that is acknowledged to be the largest rough gem-quality diamond ever discovered in the world and has a body mass of 3,106.75 carats (621.35 g).

  • CURB LINK CHAIN

    A chain with oval links that are twisted to lie flat.

  • CUSHION CUT

    A cushion cut stone is a square or rectangular cut with rounded corners and multiple facets for maximum light refraction.

  • CUT

    The cut of a diamond refers, first of all, to its shape. Diamonds are cut into many different shapes, reflecting not only popular taste but the proportions and quality of the rough stone.

  • CUT, FAIR

    While still capturing some sparkle, this cut lacks brilliance and proportion when compared to the Good and Very Good cuts.

  • CUT, GOOD

    Good cut grade of a diamond helps reflect light to obtain a good amount of brilliance, though not equal to the Excellent or Very Good cut. Thus it demands a much lesser price.

  • CUT, IDEAL

    This is when the diamond is perfectly proportioned with the highest grade of polish and symmetry. These stones reflect just about all the light that enters. They are the most brilliant, rare and one of the finest diamonds.

  • CUT, POOR

    Poorly cut diamonds with proportions and finish that make them look relatively lifeless to the eye.

  • CUT, SUPER IDEAL

    The term Hearts and Arrows is used to describe the visual effect achieved in a round Super Ideal Cut diamond with perfect symmetry and angles that exhibit a crisp and complete pattern of Hearts & Arrows. When viewed under a special magnifying viewer, a complete and precise visual pattern of 8 hearts is seen while looking down through the pavilion, and 8 arrows can be seen when viewing the stone in the table up position.

  • CUT, VERY GOOD

    Very good cut diamonds reflect most of the light that enters them, dispersing a good deal of brilliance. With these diamonds, the diamond cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond.

  • CUTTER

    Any workman engaged in the cutting and polishing of diamonds.

  • CUTTING

    The way in which the shape and facet arrangement of a diamond or gemstone is designed.

  • CVD

    Chemical vapour deposition of diamond or CVD is a method of producing synthetic diamond by creating the circumstances necessary for carbon atoms in a gas to settle on a substrate in crystalline form.

D

  • DCLA

    The Diamond Certification Laboratory of Australia (DCLA) is one of the world's foremost independent diamond grading and certification laboratories.

  • DE BEERS

    The De Beers Groups is one of the largest diamond trading companies providing exquisite collection of diamonds to the clients. All diamonds in De beers are characterized by beauty, fire, life and brilliance.

  • DEEP CUT

    When a diamond is cut too deep, it will lose or leak light through the side or bottom. This results in less brilliance and value.

  • DENSITY

    Density is defined as the ratio of the mass of an object to its volume.
    Density should correctly be expressed in units of "unit mass per unit volume", e.g. grams per cubic centimetre. The figure quoted is often the same as that for specific gravity. For those who are unsure what "mass" means, consider it to be the same as "weight", you will not be far out.

  • DEPTH

    Depth is the distance from the very top of a diamond or gemstone to the very bottom of a diamond or gemstone.

  • DEPTH PERCENTAGE

    Depth percentage, which expresses how deep the diamond is in comparison to how wide it is. This depth percentage of a diamond is important to its brilliance and value.

  • DEPTH & TABLE PERCENTAGES

    The table percentage of a diamond represents the ratio of table width to overall stone width. Like depth percentage, the lustre of the stone is directly affected by its table percentage.

  • DESIGN

    Jewellery that is often designed to cater to a certain trend or fad. Designer jewellery can also refer to a line created by a specific jewellery craftsman.

  • DIAMANTAIRE

    Anyone professionally involved with diamond manufacturing or marketing

  • DIAMANTIFEROUS

    Diamond-bearing ground.

  • DIAMETER

    The Diameter is a type of measurement used for circles (or other round objects). The diameter measurement is used in the piercing industry to determine the size of a ring used in piercings, to ensure that the correct size is worn.

  • DIAMOND

    Diamond is the eternal and most precious gemstone of the world. The name diamond was derived from an ancient Greek word, 'adamas' which means 'invincible'. Diamond belongs to the class of native metals and is a member of the group of Carbon.

  • DIAMOND CERTIFICATE

    A certificate issued to a diamond by the Gemmological Institute of America (GIA) or others, upon successfully passing the diamond-grading. The Certificate gives a complete and detailed description of the diamond, listing the 4C's.

  • DIAMONDOID

    A diamondoid, in the context of building materials for nanotechnology components, most generally refers to structures that resemble diamond in a broad sense: namely, strong, stiff structures containing dense, 3-D networks of covalent bonds, formed chiefly from first and second row atoms with a valence of three or more. Examples of diamondoid structures would include crystalline diamond, sapphire, and other stiff structures similar to diamond but with various atom substitutions which might include N, O, Si, S, and so forth. Sp2-hybridized carbon structures that – in contrast to sp3-hybridized carbon in diamond – arrange in planar sheets ("grapheme" sheets) are sometimes also included in the class of diamondoid materials for nanotechnology, e.g., graphite, carbon nanotubes consisting of sheets of carbon atoms rolled into tubes, spherical buckyballs and other grapheme structures.

  • DIAMOND GAUGE

    An instrument that is used to measure a diamond's length, width and depth in millimetres.

  • DIAMOND GRADING REPORT

    Documents issued by gemmological laboratories that evaluate a diamond's cut, clarity, colour and carat.

  • DIAMOND SAW

    A diamond-charged blade used as a cutting edge in fashioning coloured stones or in various applications in industry.

  • DIAMOND SURE

    Well-conceived and highly effective synthetic diamond detection instrument.

  • DIAMOND SYNDICATE

    One of the names by which De Beers, with its inter-related companies, is known. Many diamond syndicates have been formed at various periods of time, to purchase large important diamonds.

  • DIAMOND TRADING COMPANY, LTD

    A De Beers-owned company (DTC) that sells rough diamonds to diamond merchants.

  • DIAMOND TWEEZERS

    Tweezers with rounded ends, corrugated tips and rather a weak spring to hold diamonds and other stones.

  • DIAMOND VIEW

    Diamond View works by producing a fluorescence image of a diamond. Specifically, Diamond View uses a camera to display the fluorescence pattern created on the surface of a diamond after it has been exposed to shortwave UV light. Given that the fluorescence colours and patterns from synthetic diamonds differ greatly from those of natural diamonds, Diamond View makes it possible for gemmological laboratories and jewellery professionals to determine whether a diamond is natural or synthetic. In addition, by obtaining a phosphorescence image, Diamond View also makes it possible to detect whether Type II diamonds could be near colourless synthetics.

  • DIAMOND WEDDING ANNIVERSARY

    60th Wedding Anniversary

  • DIAMONIQUE

    Diamonique is a registered trade mark, belonging to QVC Inc., and the brand name they choose to use for cubic zirconia, a popular diamond simulant.

  • DIMENSIONS

    In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify each point within it.

  • DIRECTION

    Direction is the information contained in the relative position of one point with respect to another point without the distance information.

  • DISPERSION

    Dispersion is the difference between the amounts of refraction of different colours of light. White light is actually composed of light of all different colours.

  • DODECAHEDRON

    A twelve-sided geometric solid. One of the crystal forms found in the Isometric crystal system.

  • DOP

    A cutter's holding device used while polishing diamond. The dop would be held by the tang. In some automated diamond cutting systems the dop and tang are incorporated into one design.

  • DOUBLE REFRACTION

    When a ray of light enters a crystal having a Trigonal system in directions other than the optic axis, it splits into two distinct rays. This is known as double refraction.

  • DRESDEN

    41 carats, most likely from India. This pear shaped green diamond's early history is not known. In around 1700 it was in the possession of August the Strong, Duke of Saxony. Kept in the Green Hall in Dresden, hence its name.

  • DRILL, DRILLS, DRILLING

    As the name specifies, in this step a small hole is created through the stone, such stones are known as beads.

  • DRILL BIT

    Drill bits are cutting tools used to create cylindrical holes.

  • DROP EARRINGS

    Drop earrings have a classical appeal in all the ages. From the name we can easily guess that drop earrings are earrings, which drop down from the earlobe.

  • DURABILITY

    Hardness 10 on Mohs scale. The hardest natural substance. Diamonds can be cut and polished only with other diamonds, and only because of slight directional differences in hardness and a perfect octahedral cleavage.

  • DUTCH ROSE

    A typical rose cut diamond has a unique shape and facet arrangement. It has a flat bottom and an elevated pointed dome with triangular facets forming a point. The dome is generally in the shape of a hemisphere or pyramid. The number of triangular facets in a rose cut diamond may vary between 12 to 24. Generally it has a lower tier of triangular facets which in combination with the upper tier, gives the look of a rose bud. The facets in the upper tier are called star facets and the ones in the lower tier are known as the diagonal facets. Usually, the middle portion of a rose cut diamond has six triangular facets, which meet at a point in the centre. The outline of this diamond is usually circular but there are oval, hexagonal and pear-shaped domes. The facet arrangement in rose cut diamonds are usually in multiples of six.

E

  • EGL

    European Gemmological Laboratory - EGL has franchises in a number of cities around the world which grade diamonds.

  • EIGHT CUT

    This has 8 facets on the upper and lower parts as well, plus the table. It is used for small stones.

  • ELEMENT SIX

    Element Six is a subsidiary of De Beers and the world's leading manufacturer and supplier of industrial Diamond super materials. Element Six operates globally with its head office registered in Luxembourg, and primary manufacturing facilities in China, Germany, Ireland, Sweden, South Africa and the UK.

  • EMERALD

    Emeralds, like all coloured gemstones, are graded using four basic parameters – the four Cs of Connoisseurship: Colour, Cut, Clarity and Crystal. The last C, crystal is simply used as a synonym that begins with C for transparency or what gemmologists call diaphaneity. Before the 20th century, jewellers used the term water as in "a gem of the finest water" to express the combination of two qualities, colour and crystal. Normally, in the grading of coloured gemstones, colour is by far the most important criterion. However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree of transparency to be considered a top gem.

  • EMERALD CUT

    A form of "step cutting." It usually is rectangular but sometimes is square, in which case it is known as a square emerald cut. It has rows (steps) of elongated facets on the crown and pavilion, parallel to the girdle, with sets on each of four sides and at the corners. The number of rows, or steps, may vary, although the usual number is three on the crown and three on the pavilion. The emerald cut is seldom used for diamonds in the intermediate colour grades, since it tends to emphasize colour. It is excellent, however, for colourless stones and when it is desirable to emphasize the colour of fancy colours.

  • ENGRAVE

    To decorate metal by gouging a design with graver's tools; embellishing metal or other material with patterns using a stamping tool or drill. This was a popular technique in mid-Victorian jewellery.

  • ENHANCEMENTS

    Gemstone enhancement is defined as any treatment process that is used to improve the appearance, durability or availability of a gemstone.

  • EUROPEAN CUT

    Style of diamond cutting popular from approximately 1890 to the 1930s typified by a round girdle, a smaller table in relation to the diameter of the stone, and a large culet.

  • EXTRA FACET

    An asymmetrical and irregularly placed facet that is not part of the original faceting scheme.

  • EYE CLEAN

    A term used to describe a diamond that has no flaws visible to the unaided eye of a diamond expert, usually misused.

F

  • FACE

    A term used for flat or plane surface that make up the exterior form of a crystal.

  • FACET

    A facet is one of the flat surfaces of a cut stone or glass.

  • FACETING

    Faceting is the cutting and polishing of the surface of a stone.

  • FANCY COLOURED DIAMOND

    A Diamond that exhibits a strong colour, such as yellow, as opposed to an off coloured white Diamond. Fancy coloured Diamonds can be very expensive and are often highly prized by collectors.

  • FANCY CUT OR FANCY SHAPE

    A diamond cut in any shape other than round. Fancy cuts include such shapes as baguette, emerald, triangle, pear, princess, oval and marquise.

  • FANCY DIAMOND

    Fancy diamond refers to a strong colour property of a diamond. A diamond that has a distinctive colour, such as red, blue, yellow or any other is called a Fancy Diamond.

  • FEATHER

    Feather inclusions (Ftr) are caused by cleavage planes or internal stress fractures that have the appearance of wispy feathers.

  • FILIGREE

    Filigree is gold or silver wire that have been twisted into patterns and soldered into place. Openwork filigree is not soldered onto a sheet of metal and is difficult to make. Imitation filigree is made of stamped metal.

  • FILL, FILLED, FILLING

    Diamond clarity is sometimes improved and enhanced by filling tiny fractures or feathers with molten glass, much like you would repair a crack in a car's windshield glass.

  • FINDING

    The component parts or materials used in making a piece of jewellery.

  • FINISH

    Refers to the surface quality of a gemstone or piece of jewellery.

  • FIRE

    Fire is the common name for the effect caused by dispersion.

  • FISHEYE

    Diamond with a pavilion depth of less than 40 per cent, in which a circular grey reflection of all or part of the girdle appears through the table when the stone is examined face-up.

  • FISHHOOK CLASP

    Also called a Hook and Eye Clasp, this fastener has a hook on one end of the chain and a metal loop on the other. The hook fits through the loop to keep the chain together.

  • FISSURE

    A fissure is an elongated fracture or crack in the surface of a diamond.

  • FLAT STONE

    A diamond brilliant with a very thin crown and pavilion.

  • FLAW

    Flaw refers to any internal or external imperfection on a gemstone and usually includes scratch, feather, fissure, carbon spot, knot, etc.

  • FL OR FLAWLESS

    Flawless is a term used for a gemstone that is without any internal or external flaw when viewed by a trained eye under 10X magnification.

  • FLORENTINE FINISH

    Florentine finish is a surface finish pattern made up of a series of engraved lines crossed lightly by perpendicular lines or cross-hatching.

  • FLUORESCENCE

    Fluorescence refers to a diamond's tendency to emit a soft coloured glow when subjected to ultraviolet light (such as a "black light"). Roughly 30% of diamonds fluoresce to some degree.

  • FLUSH SETTING

    A setting style in which the entire gemstone is sunk into the metal of the jewellery so that only the top is visible.

  • FOUR CS

    Four important factors that control a diamond's appearance and durability are often lumped together and called the Four Cs: diamond colour, clarity, cut and carat weight.

  • FOXTAIL CHAIN

    A foxtail chain is an intricate chain featuring three rows of links braded together.

  • FRACTURE

    Fractures are caused mainly by mechanical stresses like pressure or impact and may run in all directions within the diamond.

  • FRACTURE FILL, FILLED, FILLING

    In diamonds, fracture filling entails a molten glass filling that improves clarity. You can get a lot more stone for your money buying fracture filled diamonds, the problem is that the treatment isn't always permanent.

  • FRENCH WIRE

    A curved wire which passes through the pierced earlobe and has a catch closure. Used mostly in dangling earrings.

  • FULL-CUT BRILLIANT

    A brilliant-cut diamond or coloured stone with the usual total of 58 facets.

  • FUZZY GIRDLE OR BEARDED GIRDLE

    Tiny, numerous, hair like fractures extending into the stone.

G

  • GABRIELLE CUT

    The cut was created by, and named for, the master diamond cutter Gabriel S. "Gabi" Tolkowsky, the great-nephew of Marcel Tolkowsky who, as a math student in London in 1919, set the exact parameters for the perfect round brilliant cut with 58. The Gabrielle diamond stands out for its 105 facets (47 more than the ideal cut which has only 58) which allow for an unparalleled brilliance. The cutting style is also known as a "triple brilliant" and is available in classic rounds and all the fancy shapes: the marquise, oval, pear, square or princess (known as carre), emerald and heart. It is available in sizes of .50 carats and up.

  • GAGTL, G.A.G.T.L.

    Gemmological Association and Gem Testing Laboratory of Great Britain (BUAC)

  • GAUGE, GAUGES

    A measuring device for determining diameters, thickness, height, etc.

  • GEM

    A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.

  • GEM-A

    The Gemmological Association of Great Britain

  • GEM DEFENSIVE PROGRAMME

    Gem Defensive Programme has as its primary goal, the development of reliable methods to separate natural diamonds from these new synthetic diamonds.

  • GEMOLOGIST, GEMMOLOGIST

    A person who has successfully completed recognized courses in gemmology and has proven skills in identifying and evaluating gem materials.

  • GEMSCOPE

    High-resolution diamonds imaging microscopic view of diamonds.

  • GEMSCRIBE

    GEM Scribe is a powerful automatic diamond inscription system which allows you to inscribe on the stone's girdle for any conceived purpose.

  • GEMSTONE

    A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.

  • GIA

    The Gemmological Institute of America. The GIA was established in 1931 as a non-profit educational resource for the gem and jewellery industry.

  • GIRDLE

    Girdle is the widest part or outer edge of the gemstone and the dividing line between the crown and pavilion. The girdle can be rough (matt), faceted, polished or unpolished but a polished or faceted girdle doesn't improve a gemstone's grade.

  • GIRDLE FACETS

    The 32 triangular facets that adjoin the girdle of a round brilliant-cut stone, 16 above and 16 below. Also called upper- and lower-girdle facets, upper- and lower-break facets, top- and bottom-half facets, skew facets or cross facets.

  • GIRDLE REFLECTION

    When a diamond has a pavilion that is too shallow or flat, the girdle is seen reflected in the table.

  • GIRDLE THICKNESS

    The average thickness of the gemstone's girdle, which is the junction between the crown and pavilion of the stone.

  • GIRDLING

    Girdling is the process of giving a circular shape to a gemstone. In this process, a gemstone is held in a lathe, or in a cutting machine, and cut or shaped by another diamond or tool, called a sharp.

  • GOLD

    Gold is the most malleable and ductile metal; a single gram can be beaten into a sheet of one square meter, or an ounce into 300 square feet. Gold leaf can be beaten thin enough to become translucent.

  • GRADING REPORT

    Diamond Grading Reports: There are many recognized gemmological laboratories that can grade your diamond for a fee. The most well know is the GIA, Gemmological Institute of America.

  • GRADUATED

    Graduated refers to a piece of jewellery where the beads start of small at the clasps and then progressively increase in size toward the middle.

  • GRAIN CENTER

    A small area of concentrated crystal structure distortion, usually associated with pinpoints.

  • GRAINER

    An old style term used to describe carat weight in 1/4 carat increments. A two grainer is a 1/2 carat, a 3 grainer is a 3/4 carat, etc.

  • GRAINING

    Indications of irregular crystal growth. May appear milky, like faint lines or streaks, or may be coloured or reflective.

  • GREEN GOLD

    Green gold: is a coloured gold finish that has a slight green hue due to the addition of silver as an alloy.

  • GYPSY SETTING

    The stone is set into a solid piece of metal by drilling a recess into the metal, placing the stone in the hole and then forming the metal at the edge of the hole back over the stone to secure it.

H

  • HARDNESS

    Diamond is renowned for its hardness. Hardness is the measure of a substance's resistance to being scratched, and only a diamond can scratch another diamond. Diamond is the hardest substance known.

  • HATTON GARDEN

    Hatton Garden is a street and area near Holborn in London, England. It is most famous for being London's jewellery quarter and centre of the UK diamond trade, but the area is also now home to a diverse range of media and creative businesses.

  • HEAD

    Head refers part of the setting that holds the centre stone or solitaire in place.

  • HEART-SHAPED DIAMOND

    A "fancy cut" diamond or stone in the shape of a heart.

  • HEAVY (HEAVILY) SPOTTED

    Extremely spotted diamond.

  • HEIGHT

    The height of a pendant, earring, or other piece of jewellery as measured vertically from the top to the bottom. This measurement is usually a closely estimated average.

  • HERRINGBONE CHAIN

    A chain made up of short, flat, slanted parallel links with the direction of the slant alternating row by row resembling the spine of the herring.

  • HIDDEN CLASP

    A clasp that has an additional safety. To open, unsnap the safety latch, push down on the tab until it unlocks, and gently pull apart.

  • HIGH-POLISH FINISH

    A piece of jewellery that has been polished to a mirror-like finish.

  • HOOP EARRINGS

    Hoop earrings are simply earrings in the shape of a hoop or circle.

  • HOPE

    The 45.52 carat steel blue Hope Diamond was found in India back in remote times as a rough crystal weighing 112 carats.

  • HRD

    'De Hoge Raad voor Diamant' is a prestigious independent European gemmological certification laboratory based in Antwerp, Belgium that began grading diamonds and providing grading reports in 1976. The HRD does not sell diamonds, but acts as a consultant in the grading of precious gems. It is important to note that a grading report provided by any gemmological laboratory is NOT a statement of the monetary value of a particular stone (like an appraisal), but a professional opinion that evaluates only its quality.

  • HUE

    Hue is the term used for the actual colour of the spectrum (red, orange, yellow, green, blue, indigo or violet). The more pure a gemstone's hue, the more valuable.

I

  • IGI

    International Gemmological Institute. A laboratory which offers a diamond grading report.

  • ILLICIT DIAMOND BUYING

    It has been calculated by persons engaged in the business than 12 per cent. of the fall in the price of rough diamonds which has taken place within the last few years should be set down to the sale of stolen gems, which, to the value of more than 500,000, annually find their way to be markets.

  • ILLUSION SETTING

    Used for smaller diamonds, this setting supports one or more diamonds in prongs within a larger surface of white gold, which is in turn supported in a larger setting, thus giving the "illusion" of a larger diamond.

  • IMITATION

    Imitation gemstones can be anything that resembles a natural gemstone but does not have the same physical characteristics or chemical composition. These items are usually much less expensive than the natural forms.

  • INCIDENT RAY

    The 'incident ray' is the ray of light that strikes the surface before reflection, transmission, or absorption.

  • INCLUDED OR IMPERFECT

    An internal flaw, or inclusion, within the diamond crystal. This is a separate crystal within the diamond crystal matrix. It is often simply another diamond crystal.

  • INCLUDED CRYSTAL

    Mineral crystals, such as garnet or peridot, contained inside a diamond.

  • INCLUSION

    In gemstones, an inclusion is any solid, liquid, or gaseous foreign body enclosed in the mineral or rock. The price of Amber can vary greatly based on the type of inclusions and clarity of the stone.

  • INDENTED NATURAL

    The portion of the original rough diamond's surface which is left on the polished diamond dips slightly inward, creating an indentation.

  • INLAID SETTING

    A portion of the metal setting has been cut away and replaced by a stone. In this setting, the stones are flush with the metal surface.

  • INTERNAL GRAINING

    Internal indications of irregular crystal growth. May appear milky, like faint lines or streaks, or may be coloured or reflective.

  • INVISIBLE SETTING

    A setting where stones are placed very closely together in a metal framework below the surface so that the metal cannot be seen. Stones sit side-by-side, giving them the appearance of a continuous surface.

  • IRIDIUM

    Iridium is a metal that is similar to platinum and are commonly alloyed together in order to decrease the cost of a piece of jewellery.

  • IRON

    Iron is a metal rarely used in jewellery since it is so brittle and lacks lustre (except in its mineral forms, pyrite or marcasite). Iron jewellery was popular in Germany in the early 1800's during the war with Napoleon.

  • IRRADIATED DIAMOND

    A diamond which has been exposed to radiation.

J

  • JEWELLER'S LOUPE

    Loupe is a French word for magnifying glass. It is a small magnifying lens used to examine gemstones. 10X magnification is the standard

  • JEWELLERY CLEANER

    A solution that usually incorporates water and a mild detergent, although many often contain small amounts of ammonia.

  • JEWELLERY POLISHING CLOTH

    Cloth used to clean and polish jewellery safely.

K

  • KIMBERLEY

    Kimberley is a city in South Africa, and the capital of the Northern Cape. It is located near the confluence of the Vaal and Orange Rivers. The town has considerable historical significance due its diamond mining past and siege during the Second Boer War. Notable personalities such as Cecil Rhodes made their fortune here and the roots of the De Beers corporation can also be traced to the early days of the mining town.

  • KIMBERLEY OCTAHEDRON

    The Kimberley Octahedron is an uncut diamond discovered in 1964 in South Africa in the Dutoitspan mine, one of the diamond mines situated in the Kimberley region of South Africa. The name of the diamond reflects its place of origin, the internationally renowned diamond producing region where the first diamonds were discovered in 1871.

  • KIMBERLEY PROCESS

    KPCS was introduced by United Nations General Assembly Resolution 55/56 following recommendations in the Fowler Report. The process was established in 2003 to prevent diamond sales from financing rebellious movements. The certification scheme aims at preventing "blood diamonds" from entering the mainstream rough diamond market. It was set up to assure consumers that by purchasing diamonds they were not financing war and human rights abuses.

  • KIMBERLITE

    Kimberlite is a type of potassic volcanic rock best known for sometimes containing diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.7 g) diamond in 1871 spawned a diamond rush, eventually creating the Big Hole.

  • KNIFE-EDGE GIRDLE

    A very thin, knife-edge like girdle on a diamond. Not very desirable, since such a girdle is vulnerable to chipping.

  • KNOT

    A knot is a flaw (a mineral inclusion) in a gemstone (usually a diamond) that is at the surface of a gem after polishing. The knot is a small raised bump on the finished gemstone.

  • KOHINOOR, KOH-I-NOOR, KOH-I-NUR

    Persian for "Mountain of Light," one of the world's most famous diamonds, weighing 186 carats until recut in 1852 to 108.93 carats. Dating back 5,000 years, it was found in India, and is presently in the English Crown Jewels.

L

  • LASER DRILLED

    A diamond treatment that involves using a concentrated beam of laser light to drill to a diamond's dark inclusions and disguise or alter them.

  • LASER DRILL HOLE

    A tiny tube made by a laser. The surface opening may resemble a pit, while the tube usually looks needle-like.

  • LASER INSCRIPTION

    The laser etched text put on diamond girdle for identification, usually consisting of the grading laboratory initials and the certification number.

  • LATCH EARRING BACK

    The hinged arm closes and snaps into the U-shaped lock.

  • LEAKAGE

    Areas that do not return light.

  • LENGTH-TO-WIDTH RATIO

    A comparison of how much longer a diamond is than it is wide, used to analyse the outline of fancy shape diamonds.

  • LIGHT YELLOW

    A trade term used by some dealers to cover a wide range of colours in the low end of the diamond colour-grading scale. Stones in the broad classification show a very obvious yellow tint to the unaided eye.

  • LOBSTER CLAW CLASP

    An interlocking catch with a spring mechanism and a safety lock.

  • LONSDALEITE

    Lonsdaleite (named in honour of Kathleen Lonsdale), also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with a hexagonal lattice. In nature, it forms when meteorites containing graphite strike the Earth. The great heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified in 1967 from the Canyon Diablo meteorite, where it occurs as microscopic crystals associated with diamond.

  • LOOSE

    An un-mounted, polished diamond

  • LOT

    A group of rough diamonds offered for sale by the Diamond Trading Co. to firms invited to view its "sights." A lot usually includes a wide variety of material.

  • LOUPE CLEAN

    Describing a flawless gem; no visible inclusions under 10X magnification.

  • LOWER GIRDLE FACET

    A facet on the pavilion of a round brilliant just below the girdle.

  • LOWER-HALF LENGTH PERCENTAGE

    Lower-Half Length Per cent is the average lower half-length relative to the distance between the girdle edge and the centre of the culet, listed to the nearest 5 per cent [5%].

  • LUMINESCENCE

    Luminescence is emission of light by a substance not resulting from heat; it is thus a form of cold body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions, or stress on a crystal.

  • LUSTRE, LUSTER

    Is the degree to which a diamond or gemstone reflects light.

M

  • MACLE, MACLES

    A twinned rough diamond crystal, often triangular and flattish. Also spelt maccle, maccles

  • MADE

    Created by humans rather than occurring in nature.

  • MAIN FACETS

    The first sixteen facets to be ground onto rough diamonds, apart from the table and culet, also the main pavilion facets (the first eight on the pavilion).

  • MAKE

    Make of a diamond refers to how well a stone is cut and faceted to bring out the full beauty of the rough crystal. Good proportions, symmetry, and polish effect the beauty of a diamond much more than perfect colour or clarity.

  • MARCASITE

    Chemical composition -- Iron sulfide. Often confused with pyrite or fool's gold, a slightly denser form of iron sulfide that crystallizes in the isometric (cubic) system.

  • MARQUISE CUT

    The Marquise Cut is a very popular cut which is used to give appropriate and striking shapes to the diamonds. It is mainly employed to produce designer jewellery which have a good market in today's global world.

  • MASTER, MASTER STONE

    Master stones are carefully selected diamonds used by diamond grading laboratories for colour comparison; they are also distributed for use by others who need to grade diamonds accurately.

  • MASTER SET

    A set of colour comparison diamonds that defines diamond colour grades in the normal (D-to-Z) range.

  • MELEE

    Classification used in the sorting of diamonds weighing less than carat.

  • METAL

    Metals commonly used in the metalsmith's studio can be divided into two groups. Coloured metals would include pure gold, most gold alloys, copper, and non-precious alloys such as brass or bronze.

  • MILLEGRAIN, MILGRAIN

    Literally a thousand grains, setting style where a large number of small grains of metal are raised up to create the diamond setting, a form of rim or bezel setting.

  • MILLENIUM STAR

    The Millennium Star is a famous diamond owned by De Beers. At 203.04 carats (40.608 g), the world's second largest known top-color (D), internally and externally flawless, pear-shaped diamond.

  • MILLIMETER

    The millimetre (American spelling: millimeter, symbol mm) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length.

  • MINE CUT DIAMOND

    Differs from the modern Brilliant cut only in its girdle shape, which is square instead of round, a higher crown, smaller table, deeper pavilion, and larger culet, but the number and arrangement of the facets are the same.

  • MIXED-CUT

    A way in which diamonds are cut. Mixed-cut diamonds combine the qualities of the brilliant and step-cuts.

  • MODEL, MODELS, MODELLING

    A physical model (most commonly referred to simply as a model, however in this sense it is distinguished from a conceptual model) is a smaller or larger physical copy of an object. The object being modelled may be small (for example, an atom) or large (for example, the Solar System).

  • MODERN BRILLIANT CUT

    Often known as the brilliant, round, round brilliant, or "brill.". Has 58 facets, including the table and culet.

  • MODIFIED BRILLIANT CUT

    The modified brilliant cut is a classification for diamond shapes that include fancy shapes such as the oval, pear, marquise, heart and Trillian.

  • MOH'S SCALE

    The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.

  • MOISSANITE

    An extremely rare natural occurring mineral scientifically known as Silicon carbide is a compound made of ceramic components of silicon and carbon that is feigned on a bulk scale for utilizing essentially as an abrasive.

  • MOUNT

    The mount in which a gemstone is set in a finger ring, pendant, brooch, etc. The method in which a stone (or stones) is secured in a finger ring, either by a close setting or an open setting, in contrast to the method of incrustation.

  • MOUNTING

    Mounting is the process of setting or attaching a gemstone or diamond. It's also a piece of jewellery, into which gemstones or diamonds can be set.

N

  • NAIL HEAD, NAILHEAD

    Round brilliant diamond with a dark centre which resembles the head of a nail; caused by a pavilion depth greater than 48 per cent.

  • NATURAL

    A part of the original natural surface of the diamond crystal left unpolished on the girdle by the cutter striving for maximum weight retention.

  • NATURAL GEMSTONE

    Any gemstone that that occurs in nature and is not created in a laboratory.

  • NEEDLE

    The crystal or mineral inclusions in the shape of long thin needles are referred as needle flaws. In few cases, these can be of different colour that is clearly visible in the colourless Diamond.

  • NICK

    Small chip or indentation on the surface of a diamond. Usually found on the girdle.

  • NICK SETTING

    The nick setting is similar to the channel setting. Stones are placed in a row, with metal bordering either side. In a nick setting, small prongs are nicked from the surrounding metal to secure the stones.

  • NICKEL

    A hard, bright, silver-white metallic element of the iron group that is malleable, ductile, and resistant to corrosion.

O

  • OFF-CENTER CULET

    A culet that, due to differences in the angles of the opposite pavilion facets, is off centre with respect to the girdle outline.

  • OFF-MAKE

    A poorly cut or proportioned diamond.

  • OLD EUROPEAN CUT

    A round Brilliant cut with 58 facets, similar to the old mine cut, first appearing in around the 1880's. It is characterized by a deep pavilion, high crown, and an open culet.

  • OLD MINE CUT

    Commonly called Old Miners, the Old Mine Cut has a large culet, a high crown, a small table and is somewhat square, with rounded corners, in outline.

  • OPEN CULET

    A term for a culet that is larger than a normal culet.

  • OPEN TABLE

    A term describing a larger than normal table facet.

  • OPTICAL PROPERTY

    A gemstone's ability to interact with light. Some optical properties are colour, dispersion and fluorescence.

  • ORLOV

    The Orlov (sometimes spelled Orloff) is a large diamond that is part of the collection of the Diamond Fund of the Moscow Kremlin. The origin of this resplendent relic – described as having the shape and proportions of half a hen's egg – can be traced back to the 18th century Sri Ranganathaswamy Hindu temple, in Srirangam, Tamil Nadu and India where it once served as the eye of the presiding deity.

  • OVAL CUT

    An elliptical shaped diamond or gemstone that is slightly oblong.

P

  • PALLADIUM

    One of the white metals belonging to the platinum group, palladium is sometimes alloyed with gold. It is less expensive than platinum. It does not tarnish, has good working properties and weighs only a little more than half as much as platinum, making it a favored for use in jewelry.

  • PARCEL, PARCELS

    Gems sold as a group.

  • PAVÉ

    Pavé is a style of jewelry setting in which numerous small diamonds are mounted close together to create a glistening diamond crust that covers the whole piece of jewelry and obscures the metal under it.

  • PAVILION

    The pavilion is the lower sloping portion of a cut and faceted gemstone.

  • PAVILION ANGLE

    The angle measured between the girdle and the pavilion main facet.

  • PAVILION FACET

    Also often simply called pavilion facets, these are the eight large four-sided facets which run from the bottom point or culet, to the girdle.

  • PERFECT

    Only D colour and flawless diamonds should be described as perfect.

  • PEAR SHAPE DIAMOND

    The modified brilliant-cut pear shaped diamond is a combination of a round and a marquise shape, with a tapered point on one end. The diamond is always worn with the narrow end pointing toward the hand of the wearer.

  • PERFECT, PERFECTION

    Only D colour and flawless diamonds should be described as perfect.

  • PHOSPHORESCENCE

    A lingering emission of light following exposure to Ultraviolet light or other energy.

  • PHOTOLUMINESCENCE

    The emission of visible light by a diamond due to the incidence of light of a different wavelength, including fluorescence and phosphorescence.

  • PICK

    A "pick" is when a buyer is permitted by the seller to select one or more diamonds from a parcel.

  • PICKING PRICE

    Normally a higher price is charged to a buyer wishing to take one or more selected stones from a parcel, this is known as a picking price.

  • PINK DIAMOND

    One of the rarest and most desirable colours for diamond.

  • PINK GOLD

    This gold is a gold and copper alloy widely used for specialized jewelry. It is also known as pink gold and red gold. As it was popular in Russia at the beginning of the nineteenth century, it is also known as Russian gold, however, this term is now archaic. Although the names are often used interchangeably, the difference between red, rose, and pink gold is the copper content – the higher the copper content, the stronger the red coloration. A common alloy for rose gold is 75% gold and 25% copper by mass (18 karat). Since rose gold is an alloy, there is no such thing as "pure rose gold".

  • PINPOINT, PINPOINTS

    Miniscule spots internal to a Diamond. A cluster of pinpoints can form a cloud.

  • PIPE, PIPES

    The common name for a vertical, columnar mass of rock that cooled and solidified in the neck of a volcano. When these rock masses consist of kimberlite, they often contain diamonds. They occur in Africa, India, Russia, Arkansas and elsewhere.

  • PIQUÉ

    A diamond so classified for its lack of clarity (or purity) as a result of its having very small inclusions (piqués) of carbonaceous material, usually visible to the naked eye.

  • PIT

    Tiny holes, often appearing as white dots, on the surface of the diamond. Smaller pits can be polished away, but larger pits on the diamond's table may require re-cutting, causing the diamond to lose weight.

  • PLATINUM

    Called the "King of Metals", platinum is a very heavy (nearly twice the weight of gold), silver-white metal that is very ductile. Although it is a soft metal, platinum is not easily scratched and is very strong and durable.

  • POINT

    A weight of one hundredth of a carat, written as 0.01 cts.

  • POLISH, POLISHED, POLISHING

    The reduction of a rough or irregular surface to a smooth flatness or curvature. In diamond fashioning, it is used to include both lapping, or blocking, and brillianteering, as well as the production of any facet; the final operation in fashioning a diamond, usually done with diamond powder on a horizontal disc, or lap, against which the diamond is held in a dop.

  • POLISH LINES

    Tiny parallel lines or surface clouding left by irregular polishing or excessive heating during polishing, respectively.

  • POLISH MARK

    Also known as "Wheel Marks," whitish film on the surface of a facet caused by excessive heat during polishing.

  • POLISHED GIRDLE

    A girdle which had been finely ground to a polished finish instead of the older and simpler matt finish left by bruting.

  • PRECIOUS METALS

    As the name suggest the precious metals and stones are those metals and stones which are rarely found and have more worth in the world market.

  • PRINCESS CUT

    A more recent adaptation of the barion is the princess cut, which often finds its way into solitaire engagement rings. Flattering to a hand with long fingers, it is often embellished with triangular gems at its sides.

  • PRONG SETTING

    The most popular style for engagement rings, prong settings consist of either 4 or 6 metal prongs that are formed around the stone and bent over the top to hold it in place.

  • PROPORTIONS

    Describes the cutting quality relative to the Table Percentage, Depth Percentage, Girdle Percentage, Crown and Pavilion angles and symmetry.

  • PROPORTIONSCOPE

    Quartz, the most common mineral found on the earth's surface is a component of almost all the types of rock. Quartz has a wide variety with respect to variety, color and forms.

R

  • RADIANT

    The Radiant Cut design was created by Henry Grossbard of the Radiant Cut Diamond Company, not so long ago in 1977. Gemstones have a total of 70 facets, combining the shape of an emerald cut gem and the sparkle of a brilliant cut square or rectangular gem.

  • RAP, RAPAPORT

    The Rapaport Diamond Report provides jewelers, diamond dealers and manufacturers with the key information they need to succeed in the diamond industry. Pricing, availability and market information in the magazine provide a critical edge in the complex and competitive diamond, gem and jewelry marketplace.

  • RAPAPORT PRICE LIST

    The Rapaport Diamond Report provides jewelers, diamond dealers and manufacturers with the key information they need to succeed in the diamond industry. Pricing, availability and market information in the magazine provide a critical edge in the complex and competitive diamond, gem and jewelry marketplace

  • RAPNET

    RapNet is the Rapaport Diamond Trading Network connecting thousands of the best diamond suppliers and buyers around the world. It is the primary market for GIA and other certified diamonds.

     

  • RATIO

    In mathematics, a ratio is a relationship between two numbers of the same kind (i.e., objects, persons, students, spoonfuls, units of whatever identical dimension), usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second (not necessarily an integer).

  • RAY

    In optics, a ray is an idealized narrow beam of light.

  • RED DIAMOND

    Red diamonds are rare, fancy diamonds and are quite valuable. Diamonds are precious, lustrous gemstones made of highly-compressed carbon; they are one of the hardest materials known.

  • REFLECTION

    When a ray of light touches the surface of a diamond, part of the light is reflected back, this is external reflection.

  • REFRACTION

    When a ray of light passes from air into a denser medium, such as a gemstone, part is reflected from the surface and part enters the gem material.

  • REFRACTIVE INDEX

    The refractive index of a gemstone is an important characteristic which helps to determine the appearance of the gem. This property can easily be measured to help in identifying gemstones.

  • RETURN OF LIGHT

    When a diamond has a high quality cut (ideal cut), incident light will enter the stone through the table and crown, traveling toward the pavilion where it reflects from one side to the other before bouncing back out of the diamond's table toward the observer's eye. This phenomenon is referred to as "light return" which affects a diamond's brightness, brilliance, and dispersion. Any light-leakage caused by poor symmetry and/or cut proportions (off-make) will adversely affect the quality of light return.

  • RHODIUM, RHODIUM PLATING

    Rhodium has a lower density and weight than platinum, but it is heavier than gold. Due to its low electrical resistance, rhodium is also used as an electroplate finish on electrical contacts.

  • RING SETTING

    Whether you're choosing a diamond solitaire or a ring with multiple diamonds, the ring setting is an integral part of the piece's design.

  • RING SIZE

    Manufactured rings are cast to industry standard sizes. Size is unisex and is number based, running in whole as well as half sizes. The "standard" size for women is size 7; for men, size 10.

  • RIVER

    Riverstones are smooth, rounded pebbles found in rivers and on beaches. They become naturally polished as water and other rocks move against them. Some say they are related to jasper.

  • ROUND CUT OR BRILLIANT CUT

    Round brilliant cut gemstones are known to have the most vibrancy and sparkle. With 57 or 58 facets radiating from the center out to the girdle, a brilliant cut maximizes the amount of light that is reflected from the core of the gemstone.

  • ROUNDING UP OR GIRDLING

    Rounding up is the process of giving a circular shape to a gemstone. In this process, a gemstone is held in a lathe, or in a cutting machine, and cut or shaped by another diamond or tool, called a sharp.

  • ROLO CHAIN

    A rolo chain is made up of symmetrical links (usually round or oval) that are connected together.

  • ROPE CHAIN

    A rope chain consists of oval links that are linked so that they produce a woven rope arising from the resultant spiral effect.

  • ROSE CUT

    A style of diamond cutting or other transparent gemstone that produces a gem with a flat base and triangular facets that rise to form a dome. This style of cut has been in use since the 16th century.

  • ROUGH DIAMOND

    Diamond as it is first found in the ground, before it has been cut and polished.

  • ROUGH GIRDLE

    A grainy or pitted girdle surface usually caused by poor workmanship.

  • ROUND BRILLIANT CUT

    Round brilliant cut gemstones are known to have the most vibrancy and sparkle. With 57 or 58 facets radiating from the center out to the girdle, a brilliant cut maximizes the amount of light that is reflected from the core of the gemstone.

  • RTZ, R.T.Z., RIO TINTO ZINC

    Rio Tinto Diamonds operates three diamond mines: the Argyle Diamond Mine in Western Australia (100% ownership), the Diavik Diamond Mine in the Northwest Territories of Canada (60% ownership), and the Murowa Diamond Mine located in Zimbabwe (78% ownership). Together, these three mines produce 20% of the world's annual production of rough diamonds, making Rio Tinto the world's third-largest producer of mined diamonds.

  • RUBY

    Ruby is the red manifestation of corundum; all other colors of corundum are referred to as sapphire. Due to its durability, brilliance and bewitching red color, it has for thousands of years been considered to be one of the most valuable gemstones.

  • RUTHENIUM

    Ruthenium (abbreviated Ruth or Ru) is a precious metal that belongs to the platinum group of metals.

S

  • SAFETY CLASP

    A safety clasp is a secure type of closure on a piece of jewelry. The term safety catch is used for a variety of these closures.

  • SAND

    Sandstone is a common type of grainy sedimentary rock that is made mostly of sand-sized grains (usually quartz) that are held together by silica, calcium carbonate, clay, or iron oxide.

  • SAPPHIRE

    Sapphires come in all ranges of colors from blue to black to colorless and all colors in between. There are no limits to the color tone or saturation of color in a sapphire.

  • SATIN FINISH

    Satin finish, also known as a brushed or matte finish, is a texturing technique used on jewelry metals where a series of tiny parallel lines are scratched on the surface with a wire brush.

  • SATURATION

    Saturation is one of three characteristics used to describe the appearance of color. Saturation (also known as intensity) refers to the brightness or vividness of a color.

  • SCAIFE

    Diamond polishing tool.

  • SCINTILLATION

    Scintillation (sparkle) is the tiny flashes of light noticeable in a diamond when the observer moves his/her head.

  • SCRATCH

    A linear indentation normally seen as a fine white line, curved or straight.

  • SCREW BACK

    A screw back is an ear nut that screws onto a threaded earring post; usually used with diamond stud earrings.

  • SCRATCHES

    These are referred to as thin lines on the surface. It is mostly formed when the stone undergoes the different steps of gemstone processing like cutting or polishing. There are very less chances that it happens naturally.

  • SEMI-MOUNT

    A semi-mount is a jewelry setting that has already been partially finished with accent gems and/or diamonds with the exception of the center stone.

  • SEMI PRECIOUS, SEMI-PRECIOUS

    A gemstone or gem (also called a precious or semi-precious stone, or jewel) is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. The traditional classification in the West, which goes back to the Ancient Greeks, begins with a distinction between precious and semi-precious stones; similar distinctions are made in other cultures. In modern usage the precious stones are diamond, ruby, sapphire and emerald, with all other gemstones being semi-precious.

  • SETTER

    Craftsman setting a gem stone into a setting.

  • SETTING

    Setting refers to the style in which a gemstone is held by precious metal into a mounting. Common settings include bezel, pave', channel or prong. Setting also refers to the part of jewelry in which one or more stones are set.

  • SHALLOW CUT

    When the cut of a diamond is too shallow, light escapes through the pavilion before it can be reflected.

  • SHANK

    The part of a ring that encircles the finger.

  • SHAPE

    Diamonds are natural crystals that come in large variety of shapes such as round, princess, heart, oval, marquise etc. The following information will help you to choose the right shaped diamond.

  • SI OR SLIGHTLY INCLUDED

    Diamond clarity grading scale. Slightly Included category (SI) diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification. The SI category is divided into two grades; SI1 denotes a higher clarity grade than SI2. These may or may not be noticeable to the naked eye.

  • SI3

    The SI3 was born out of the desire of the Diamond Industry to incorporate an extra grade to identify Diamonds in the lower range of the clarity scale. Many complained that there is too wide a gap between the SI2 and the I1 grade.
    The problem with the SI3 today is that GIA, the largest and most widely accepted Gem Laboratory in the world, does not recognize SI3 grades.
    Some say the SI3 is a good idea, some say it is a bad idea. We feel that it can be a good idea if implemented properly.
    If taken to an appraiser, our SI3 diamonds will be graded as SI3 by an EGL gemologist and as either SI2 or I1 by a GIA gemologist. Our SI3 diamonds usually appraise as SI2 with GIA we can not guarantee they will not be appraised as I1, so please keep this in mind when purchasing your diamond. If you are not satisfied with the quality of your SI3 diamond for any reason, you may upgrade it for the difference in prices between the two diamonds at no additional labor and setting costs to you.

  • SIDESTONE

    Diamonds setted around the center stone.

  • SIERRA LEONE

    Officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of 71,740 km2 (27,699 sq mi) and has a population of 6.4 million. It was a colony under the auspices of the Sierra Leone Company from March 11, 1792 until it became a British colony in 1808. Sierra Leone has a tropical climate, with a diverse environment ranging from savannah to rainforests. Freetown is the capital, largest city and economic and financial center. The other major cities are Bo, Kenema, Koidu Town and Makeni.

    Annual production of Sierra Leone's diamond estimates range between $250–300 million US$. Some of that is smuggled, where it is possibly used for money laundering or financing illicit activities. Formal exports have dramatically improved since the civil war with efforts to improve the management of them having some success. In October 2000, a UN-approved certification system for exporting diamonds from the country was put in place and led to a dramatic increase in legal exports. In 2001, the government created a mining community development fund (DACDF), which returns a portion of diamond export taxes to diamond mining communities. The fund was created to raise local communities' stake in the legal diamond trade.
    Sierra Leone is also known for its blood diamonds that were mined and sold to diamond conglomerates during the civil war, in order to buy the weapons that fuelled the atrocities of the civil war. In the 1970s and early 1980s, economic growth rate slowed because of a decline in the mining sector and increasing corruption among government officials.

  • SIEVE

    Sieving is a simple and convenient technique of separating particles of different sizes. A small sieve such as that used for sifting flour has very small holes which allow only very fine flour particles to pass through. The coarse particles are retained in the sieve or are broken up by grinding against the screen windows. Depending upon the types of particles to be separated, sieves with different types of holes are used. Separating tea leaves from tea is not considered to be sieving.

  • SIGHT, SIGHTS

    Being a sightholder has always been considered a status symbol; reaching the pinnacle of one's professional career. Before the Supplier of Choice program, criteria for becoming a sightholder were fairly standard - well established, diamond expertise, substantial capital, manufacturing capabilities, and potential to finance work in progress for several months.

  • SIGHTHOLDER, SIGHT-HOLDER

    A sightholder is a company on the Diamond Trading Company's (DTC) list of authorized bulk purchasers of rough diamonds. DTC is controlled by the De Beers Group, the single largest producer and purveyor of rough diamonds in the world. In May 2006, DTC released a list of the 93 sightholders on its website.
    The DTC Sightholder list was further reduced to 79 companies worldwide in December 2007. The list of selected companies for the 2008-2011 contract period was published in April 2008.

  • SILVER, STERLING

    Silver is a metallic chemical element with the chemical symbol Ag (Latin: argentum, from the Indo-European root *arg- for "grey" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.

  • SILVER CAPE

    Silver Cape is a type of diamond color taken from the old English method for defining diamond colors, which is disappearing today. Silver Cape diamonds are light yellow, equivalent to L, K ranking, according to color parameters set by the Gemological Institute of America (GIA). Generally, the English method defines a diamond's colors according to the mines in which it was found. The name Silver Cape, based on this method, is derived from the "Cape" mines in South Africa which yield yellowish diamonds.

  • SILVER WEDDING

    25th wedding anniversary.

  • SINGLE CUT

    Invented in the late 14th century, the "old single cut" (aka "old eight cut") diamond has the addition of corner facets to create an octagonal girdle, an octagonal table, eight bezel or crown facets, and eight pavilion facets.

  • SINGLE REFRACTION

    Single Refraction - Light that passes through a crystal without being resolved into two rays. They are also called Isotropic because light passes through them with the same velocity in all directions.

  • SIMULATE, SIMULATED, SIMULANT

    The IDC defines a simulated diamond or a diamond simulant as product that has the intention of imitating a diamond. The IDC actually does not allow companies to use the word diamond in combination with simulant, though many companies do.

  • SLIGHTLY YELLOW

    A diamond color grade that is used by some dealers for a stone showing an obvious yellow tint to the unaided eye.

  • SNAKE CHAIN

    Like the omega chain, the snake chain (also known as Brazilian chain) is also not made up of traditional linked rings. It is instead of made up of round wavy smooth metal plates joined so that it forms a flexible tube.

  • SNAP-LOCK CLASP

    A type or closure for an earring which lifts up and down in order to secure or release the earring.

  • SOC, S.O.C.

    Supplier of Choice. The Diamond Trading Company's (DTC) sales strategy is known as 'Supplier of Choice' (SoC) and was implemented in 2003. It sought to build a more efficient channel for rough diamond distribution by the DTC and maintain ethical transparency amongst the DTC's client base. SoC aims to place all De Beers diamonds into the hands of exceptionally able diamond businesses best equipped to add long term, sustainable value to them.

  • SOLDER

    A technique used in making and repairing jewelry whereby two pieces of metal are joined by applying a molten metal which has a lower melting point than the two metals being joined.

  • SOLITAIRE

    Solitaire is a piece of jewelry that features a solo stone. Most commonly refers to a ring set with a diamond. It is also the most popular style of engagement ring.

  • SORT

    Sorting is any process of arranging items in some sequence and/or in different sets, and accordingly, it has two common, yet distinct meanings. Ordering: arranging items of the same kind, class, nature, etc. in some ordered sequence. Categorizing: grouping and labeling items with similar properties together (by sorts).

  • SPARKLE

    The fire and brilliance created by light passing through a diamond.

  • SPOTS

    An inaccurate term used by some people in the jewelry industry to describe the appearance of certain inclusions in a diamond.

  • SPREAD STONE

    A diamond that comes with a large table and thin crown height.

  • SPRING RING CLASP

    A spring ring clasp is a type of clasp made in the shape of a ring. A segment of the ring can be withdrawn into the ring to allow connecting the clasp to a loop.

  • STAINLESS STEEL

    Stainless steels are a family of steels that are resistant to corrosion (rusting) and elevated temperature. They must contain at least 10.5 % chromium.

  • STAR

    Effect caused by light reflecting off inclusions inside a diamond.

  • STAR FACET

    The eight triangular facets that surround the table facet of a round, brilliant-cut diamond.

  • SQUARE EMERALD CUT

    A form of step cutting with a square girdle outline but modified by corner facets.

  • STEP-CUT

    A way in which diamonds are cut. Step-cut diamonds feature rows of facets positioned in a step-like fashion. Most step-cut diamonds have four sides and a rectangular shape, such as emerald or baguette diamonds.

  • STUD EARRINGS

    Stud earrings, also called studs, are a small, simple style of earring for pierced ears. Studs contain a single stone (such as a pearl, gemstone or diamond) or metal ball on a straight post.

  • SUPPLIER OF CHOICE

    Supplier of Choice. The Diamond Trading Company's (DTC) sales strategy is known as 'Supplier of Choice' (SoC) and was implemented in 2003. It sought to build a more efficient channel for rough diamond distribution by the DTC and maintain ethical transparency amongst the DTC's client base. SoC aims to place all De Beers diamonds into the hands of exceptionally able diamond businesses best equipped to add long term, sustainable value to them.

  • SURFACE

    Whether a polished diamond has a good surface, free of blemishes, is a quality factor.

  • SURFACE GRAINING

    Often appearing as parallel lines on the diamond's surface. Similar to polishing lines, and may be the result of irregularities in the diamond's crystal growth.

  • SURFACE MARKINGS

    Imperfections on the diamond’s surface. Often described as spots, blisters, or indentations.

  • SWISS CUT

    Halfway between a brilliant and an eight cut, with 34 facets in total.

  • SYMMETRY

    Symmetry refers to how well the diamonds facets are aligned and "pointed". GIA defines symmetry as "the exactness of shape and placement of facets".

  • SYNTHETIC DIAMOND

    Synthetic diamond is also known as cultured diamond or artificial diamond. This man-made created stone possess almost same physical and chemical properties as that of real diamonds.

T

  • TABLE

    The largest and most important facet on a round brilliant cut diamond is the table. This is the topmost facet. It is, or should be, a symmetrical octagon.

  • TABLE CUT

    A simple, obsolete cut with one "slice" cleaved or polished from (usually) an octahedral. forming a table as on a modern stone.

  • TABLE PERCENTAGE

    The table percentage of a diamond represents the ratio of table width to overall stone width. Like depth percentage, the luster of the stone is directly affected by its table percentage.

  • TABLE SIZE

    Table Size: is calculated as a percentage of the gemstone's total width. The table is described as small if its size is under 33%; acceptable if it is 33-67%; and large if it is above 67%.

  • TANG

    Most commonly used tool in the diamond polishing process.

  • TENSION SETTING

    A method of setting diamonds and other gems using only the springiness of the mount to hold the stone firm. Can look quite spectacular but rather chunky and heavy; insecure otherwise.

  • TETRAHEDRON

    Numerous mineral structures are based on the fact that tetrahedra can be inscribed in a cube. If atoms have a face-centered arrangement, we can join a corner atom to the three nearest face-centered atoms to create a tetrahedron. Diamond is one mineral that employs this structure. There are carbon atoms in a face-centered array (dark gray) plus an extra one (light gray) at the center of each tetrahedron.

  • THERMOLUMINESCENCE

    Diamond having a nitrogen content not exceeding 100 ppm and electrons or holes trapped at lattice imperfections within the crystal structure has been found to be a good thermoluminescent material. The diamond is produced by taking a diamond having a nitrogen content not exceeding 100 ppm and subjecting it to nuclear radiation.

  • THICKNESS

    Usually describing a girdle, and often expressed as a percentage of the height or depth of the diamond, often using relative terms such as "medium".

  • TIFFANY

    128.51 carats, found in the Kimberly mine of South Africa, in 1878. It weighed 287.42 carats as a rough diamond. It was bought by the jewelers Tiffany in New York and cut in Paris with 90 facets.

  • TITANIUM

    Titanium is a light, strong, lustrous metal. Pure titanium is as strong as steel and can withstand a lifetime of punishment.

  • TOGGLE CLASP

    Toggle clasps are used to secure the ends of bracelets, necklaces and chains. They are made with a bar that slips through a round, square or triangle shape.

  • TOLKOWSKY CUT

    In 1919, Marcel Tolkowsky, a member of a Belgian family of diamond cutters, published Diamond Design, the first recorded analysis of diamond proportions for the round brilliant cut diamond. His work was based on modern theories of light behavior and his opinion of what proportions resulted in what many industry professionals considered to be the best possible balance of brilliance and dispersion of light until the late 1990's.

    Tolkowsky's calculations indicate that for optimum brilliance a round brilliant cut diamond should be cut to the following angles and proportions: 34.5° Crown Angle, 40.75° Pavilion Angles, 59.3% Total Depth (excluding girdle thickness) with 16.2% of the depth being comprised of the crown (top half of the diamond) and 43.1% representing the pavilion lower half of the diamond, 53% Table based on diamond's overall diameter.

  • TONE

    Tone is one of the characteristics used to describe the appearance of color. Tone refers to the lightness or darkness of a particular stone.

  • TONGUE CLASP

    A clasp in which a V-shaped wire fits into a small tube and locks into place. On broader necklaces, the snap is square.

  • TOTAL DEPTH PERCENTAGE

    The Total Depth Percentage is the depth of a diamond, from the table to the culet, divided by the average diameter or width of the girdle. The depth of most diamonds is between 53 and 63 percent.

  • TOP LIGHT BROWN

    Most diamonds seen in High Street shops are slightly yellow or brown.

  • TOP SILVER CAPE

    Silver Cape is a type of diamond color taken from the old English method for defining diamond colors, which is disappearing today. Silver Cape diamonds are light yellow, equivalent to L, K ranking, according to color parameters set by the Gemological Institute of America (GIA). Generally, the English method defines a diamond's colors according to the mines in which it was found. The name Silver Cape, based on this method, is derived from the "Cape" mines in South Africa which yield yellowish diamonds.

  • TOP WESSELTON

    Top Wesselton refers to colors F and G, some may also call color F a Top Wesselton+ .

  • TOTAL INTERNAL REFLECTION

    Total internal reflection ian optical phenomenon that happens when a ray of light strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary, no light can pass through and all of the light is reflected. The critical angle is the angle of incidence above which the total internal reflection occurs.

  • TOUGHNESS

    Toughness relates to a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 3.4 MN m-3/2,[8] which is good compared to other gemstones, but poor compared to most engineering materials.

  • TRANSPARENT, TRANSPARENCY

    Transparency: refers to a gemstone's relative ability to transmit light.

  • TRAP CUT

    Stones whose outlines are either square or rectangular and whose facets are rectilinear and arranged parallel to the girdle are known as step- or trap-cut stones. These stones often have their corners truncated, creating an emerald cut (after its most common application to emerald gemstones) with an octagonal outline. This is done because sharp corners are points of weakness where a diamond may cleave or fracture. Instead of a culet, step-cut stones have a keel running the length of the pavilion terminus. Because both the pavilion and crown are comparatively shallow, step cut stones are generally not as bright and never as fiery as brilliant cut stones, but rather accentuate a diamond's clarity (as even the slightest flaw would be highly visible), whiteness, and lustre (and therefore good polish).

  • TREATMENT

    Artificial modification of the chemical and/or physical properties of a gemological material. In pearls, any operation for changing and improving their aspect.

  • TRIGON, TRIGONS

    A triangular indentation occurring as a growth mark on diamond octahedron faces. The sides of the trigon are reversed with respect to the face on which it occurs.

  • TRILLION OR TRILLIANT CUT

    Trillion cut is a triangular shaped diamond with truncated corners and 44 varying facets.

  • TROY WEIGHT

    The measure used to weigh Gold, Silver and jewels. In Troy weight, the pound = 12 ounces, the ounce = 20 pennyweights, and the pennyweight = 24 grains.

  • TUNGSTEN

    Tungsten also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74.

    A steel-gray metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the non-alloyed metals and the second highest of all the elements after carbon. Also remarkable is its high density of 19.3 times that of water, comparable to that of uranium and gold, and much higher (about 1.7 times) than that of lead. Tungsten with minor amounts of impurities is often brittle[4] and hard, making it difficult to work. However, very pure tungsten is more ductile, and can be cut with a hacksaw.

  • TWINNING LINES

    Visible line on or with in a fashioned diamond, caused by twinning in the crystal.

  • TWINNING WISP

    Twinning Wisp inclusions are naturally-occurring structural defects with a diamond, resulting from crystal twining during the growth process.

U

  • ULTRASONIC CLEANER

    A machine that cleans jewellery by using a fluid that is vibrated at 20,000 cycles per second.

  • ULTRAVIOLET, UV, U.V.

    Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV. It is named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet. Although ultraviolet is invisible to the human eye, most people are aware of the effects of UV through the painful condition of sunburn, but the UV spectrum has many other effects, both beneficial and damaging, to human health.

  • UNMOUNTED

    Diamond that has been removed from setting/mount.

  • UNPOLISHED

    Raw diamond before polishing.

  • UPPER GIRDLE FACET

    An upper girdle facet is one of the 16 facets found on the lower crown portion of the diamond (abutting the girdle).

W

  • WEDDING RING

    A wedding ring or wedding band is a metal ring indicating the wearer is married. Depending on the local culture, it is worn on the base of the right or the left ring finger. The custom of wearing such a ring has spread widely beyond its origin in Europe. Originally worn by wives only, wedding rings became customary for both husbands and wives during the 20th century.

  • WEIGHT RATIO

    A comparison of a diamond's weight in relation to its diameter.

  • WESSELTON

    The name Wesselton is now given to clean, well-made cut diamonds, with a quality rating between top crystal and Jagers.

  • WHITE GOLD

    White gold is an alloy of gold and nickel, sliver, or palladium. The inclusion of white metals in the alloy give white gold its silvery colour.

  • WHITE LIGHT

    White light is the effect of combining the visible colours of light in suitable proportions (the same present in solar light).

  • WISP

    Twinning Wisp inclusions are naturally-occurring structural defects with a diamond, resulting from crystal twining during the growth process.

  • WORLD DIAMOND COUNCIL, WDC, W.D.C.

    The World Diamond Council (also known during its prototype period as the International Diamond Council) is an organization consisting of representatives from diamond manufacturing and diamond trading companies. The Council was set up in July 2000 to examine ways to reduce the number of conflict diamonds entering the diamond market.

X

  • XENON

    Xenon is a chemical element with the symbol Xe and atomic number 54. A colourless, heavy, odourless noble gas, xenon occurs in the Earth's atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.

  • X-RAY, XRAY, XRAYS, X-RAYS

    X-rays can penetrate solid objects, and their most common use is to take images of the inside of objects in diagnostic radiography and crystallography. As a result, the term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. By contrast, soft X-rays hardly penetrate matter at all; the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometre.

Y

  • YAG, Y.A.G.

    Yttrium aluminium garnet is a synthetic crystalline material of the garnet group. It is also one of three phases of the yttria-aluminium composite, the other two being yttrium aluminium monoclinic (YAM) and yttrium aluminium perovskite (YAP). YAG is commonly used as a host material in various solid-state lasers.

  • YELLOW GOLD

    Even though gold is yellow when pure, the intensity of yellow colour depends on volume of other metals alloyed with it. The more the karat weight, more intense is the colour. The most popular gold alloy in yellow gold engagement rings is made up of gold, silver, copper, and often zinc.

  • YELLOW GROUND

    Weathered kimberlite which is coloured yellow.

Z

  • ZIRCON

    Zircon is a natural crystalline gemstone, which is older than diamond and is available in a pallet of colours. It is a very primitive stone whose age is approximately 4.404 billion years.

  • ZIRCONIA

    The diamond substitute known as cubic zirconia was found naturally formed in the 1930's but today it is simulated in a laboratory environment, as natural forms are no longer easily found.