|
The process of
Cut and polishing gems
is called gem Cut or lapidary, while a person who Cuts and
polishes gems is called a gem-Cutter or a lapidary.
Gemstone material that has not been extensively Cut
and polished is
referred to generally as
rough. Rough material that has been lightly hammered to knock off
brittle, fractured material is
said to have been cobbed.
All gems are Cut and polished by progressive abrasion using finer
and finer grits of harder
substances. Diamond, the hardest naturally occurring substance, has
a Mohs hardness of 10 and is
used as an abrasive to Cut and polish a wide variety of materials,
including diamond itself.
Silicon carbide, a manmade compound of
silicon and carbon with a Mohs hardness of 9.5, is also widely used
for Cut softer gemstones. Other compounds, such as cerium oxide, tin
oxide, chromium oxide, and aluminum oxide, are frequently used in
Cut & polishing gemstones. | 
