The cut of a Diamond is the only property, which is totally dependent on man. Cut refers not only to the shape and style of the diamond, but its proportions, symmetry, and finish or make.
Proportions and angles influence the internal reflection of light as well as the dispersion of light leaving the diamond. This determines the brilliance and fire (brightness and sparkle) of the diamond, and ultimately it’s perceived beauty.
Cut therefore, is actually one of the most important aspects to consider when choosing your diamond. A diamond can be cut for maximum weight recovery or maximum brilliance and beauty. Invariably one is traded of at the expense of the other. Although poor makes sell at a discount in the trade, realistically the unsuspecting retail customer will pay the same price regardless of make.
For Round brilliants there are several so called optimum cuts all with slightly different proportions. These are based on scientific formulas to maximize the return of light from the diamond. Ultimately taste and preference for the overall appearance determine the buyer’s choice.