The precision with which a diamond is cut is a critical factor in releasing its "fire" and "brilliance." It is the only factor of the 5C's that man can control.

During the cutting process, at least fifty percent of rough diamond material is usually lost. The facets, or planes, of the diamond should be placed in exact geometric relation to each other, the culet or "point" should be in the exact center of the bottom of the diamond  and the diamond needs to be well polished. This symmetry is crucial so that light entering the diamond is reflected back to the eye as brilliance. If these geometric proportions are compromised, the beauty and brilliance of the diamond are sacrificed. To achieve truly dazzling radiance, the diamond must be
well cut.