First, determine your budget; your primary consideration should be what you and your partner can comfortably afford to spend. You may wish to investigate an affordable finance option, allowing you to easily spread the cost of your ring over a fixed period of time to ease the financial burden. This may help you to upgrade your ring in terms of what you would like to buy matched with what you can comfortably afford when paying in installments.
Deciding on carat size is essentially about striking a balance between size and quality. If your partner prefers larger jewellery items and you are working within a modest budget, you can still find a larger diamond of excellent quality by carefully selecting better value combinations of colour and clarity grades.
One of the best ways to determine which size will suit her better is to find out what size she is expecting. If she has never told you consider speaking to some of her friends as they may probably know.
The girdle or edge thickness is also important as has a direct impact on the spread of the diamond. If a diamond has a very thin girdle, the stone can have a better spread, but it can chip more easily. Medium to slightly thick girdles are safest, but thicker girdles add extra weight or reduce the spread. If you want a larger size diamond for your chosen carat weight look for a diamond with a thin girdle. Ensure the girdle is thin, and not Extremely Thin or Very Thin as these can be cleaved or chipped when setting in jewellery.
The magic weights are 1/2ct, 3/4ct, 1ct, 1.5ct, 2ct etc. 'Under-sizes' are diamonds that weigh just below a magic weight. If you want a bargain 1ct diamond why not go for a 0.95cts, comparing to a 1 ct diamond of the same proportions even most jewellers wouldn’t be able to tell the difference and you could save up to 30%. Due to these factors there is a shortage of under-sizes in the market as diamond cutters always aim to achieve a magic weight. Contact one of our diamonds experts for under-sizes availability and more information on carat weight.