The cut of a diamond is responsible for its brilliance. The better a diamond is cut, the more sparkle it will have. Cut is mainly 3 things: shape, proportion, finish. Cut is the accuracy of facething and polishing of the stone to desired proportions to maximize the return of light, fire, brilliance and scintillation. The modern round brilliant cut is the basis of standard proportions in a cut. Cuts other than this are called fancy cuts.
Cut is mainly 3 things: shape, proportion, and finish. Shape is the first thing to consider in cut. Cutting pattern also falls under certain steps. The diamond-cutter has two basic cutting styles; the step cut and the brilliant cut. The step Cut is a cutting style with long, narrow, four-sided facets in rows parallel to the girdle on both crown and pavillion. The Brilliant Cut is a cutting style in which triangular and kite-shaped facets radiate from a diamond's center towards it's girdle.
Proportions of a diamond are the most important factor in its aesthetic appeal. A stone that is too deep will look small and dark while a stone that is too shallow will look too big but transparent. There is an acceptable range of proportions for table, total depth, girdle, and diameter.
Finish refers to a diamon's polish and symmetry. Polish is how clean or smooth the overall condition of the stone's surface. Symmetry is how precise the faceting pattern is done and how aligned the factes are.