Cut (gems)

When a gemstone is desired to be used in jewelry, it is cut depending on the size and shape of the rough stone, as well as the desired piece of jewelry to be made. As a general rule, a cut gemstone will reduce the mass (described in the carat) by about 50 percent.[1]

A glass crystal for decoration with about 4 cm diameter, having a facette cut often applied for gemstones. At some positions, coloured light (see rainbow colouring) can be regarded caused by the intended optical prism effect of the cut.

There are several techniques available to work with gemstones; among them are sawing, grinding, sanding, lapping, polishing, grilling, and tumbling. The diamond cut planning stage is a complex process that requires the cutter to work with unique rough stones. Very often, the location of the inclusions in a rough stone will determine the type of shape to which a diamond may be cut. For economic reasons, most diamonds are cut to retain weight instead of maximizing brilliance.[2]