Cut refers to the proportions, finish, symmetry and polish of of the diamond. These factors determine the fire and brilliance of the diamond. Well cut diamonds sell at premium and poorly cut diamonds sell at discounted prices. With the advent of new technology, the cut of the diamond can be determined through the use of the Sarin system, a computerized system which takes accurate measurements and proportions of the diamond in seconds.
Another way of calculating is the Leveridge Gauge. As an example, a round brilliant cut, which has 58 facets, is shown below. Since the quality of the cut is directly responsible for the stones’ beauty, the precision with which the facets are arranged is of prime importance. They determine the amount of light reflected to the eye, called brilliance.