Cut is the only human contribution to the diamond's beauty. The diamond was already "born" with its clarity, color and carat weight. Most important to the diamond cutter, is saving the most weight they can from the rough.

The cut refers to the diamond's shape. Diamonds can be cut into virtually any shape that you want, due to the technique of cutting with lasers. Any other shape than round, is called a fancy shape.

However, cut also refers to the diamond's finish, and proportions, measured in angles and percentages. Because the beauty of a diamond is due largely to the way it handles (reflects) light, it is crucial that some proportions and angles be close to exact, while others may have slight tolerances. There are certain dimensions that are considered "ideal" for bringing out the most brilliance (white light reflected), dispersion (rainbow-like colors reflected) and scintillation (reflection of light from movement). However, diamonds may be cut to slightly different dimensions and still be beautiful.