facetcutting

Facetcutting is the practice of shaping a gemstone by cutting flat surfaces, or facets, to improve its optical performance and overall symmetry. It is a core technique in modern lapidary and jewelry making, guiding how a rough crystal is transformed into a polished, light-reflective gem.

The process starts with evaluating the rough stone to determine its best yield and optical potential. A cutter plans table size, crown and pavilion angles, and number of facets. The rough is then preformed into a basic shape, and the stone is mounted on a dop for precise handling. Using a faceting machine equipped with index wheels, the cutter presents successive facets at controlled angles, grinding with diamond laps that transition from coarse to fine grits. After each facet is ground, it is polished with fine slurries such as cerium oxide or aluminum oxide to remove scratches and enhance brilliance. The sequence continues until the facet arrangement achieves the intended symmetry and optical performance.

Key tools include a faceting machine, diamond abrasive laps, dop sticks, pitch and polishing laps, and angle gauges. The process emphasizes accuracy in facet angles, alignment, and symmetry, since these factors influence light return, dispersion, and the stone’s apparent size.

Common cut families include brilliant cuts, which maximize sparkle, step cuts, which emphasize clarity, and mixed cuts, which blend characteristics. Facetcutting is practiced for various gemstones, with considerations for hardness, cleavage, and inclusions. Modern facetting combines traditional craft with precision machinery to produce standardized and bespoke gems.