Lapidary involves sawing, grinding, faceting, and polishing rough gem material into finished stones that maximize optical performance, durability, and weight retention. Cutters orient rough crystals to align optical axes and avoid color zoning or weak cleavage planes.
Modern equipment includes diamond-impregnated saws, silicon carbide or diamond grinding wheels, and precision faceting machines with digital angle controls. The goal is to achieve symmetry, proper facet angles based on the gem's refractive index, and a high polish that minimizes light scattering. Poor orientation or proportions can reduce brilliance by 30–50% and significantly lower market value.