Gem Cutting

The term gemcutting is used to describe the process of shaping and polishing faceted gemstones. The artisan undertaking the cutting can also be called a lapidary.While the gemstone in the rough state may be trimmed to remove undesirable material or to separate it on a cleavage line with a diamond bladed saw, accurately described as cutting and once done by the use of a chisel or similar tool to simply break off pieces that were usable as single gemstones.The actual shaping and polishing of a gemstone is a grinding or sanding process. This grinding and sanding is done using a lap, a precision metal plate embedded with grit similar to the more familiar embedding of grit on paper the lap is of high precision particularly for flatness and turned by a motor. (See faceting equipment) The grit material is normally diamond and sometimes corundum for their hardness. Only diamond is hard enough on the Mohs scale to shape and polish a diamond.The initial shaping and facet placement may be done using laps with the more familiar grits of 220, 600, 1200. The polishing step, however, requires grits that are less familiar 8,000 14,000 50,000 and even 100,000. This grit is also embedded into a metal lap, but sometimes applied manually to the lap during polishing.