There are two general types of gemstone cutting: cabochon and facet.
Cabochons, which are smooth, often domed, with flat backs. Agates and turquoise are usually cut this way, but precious stones such as rubies, emeralds and sapphires also may be. Many stones like star sapphires and moonstones must be cut this way in order to see the effects the stones have in them.
Cabochons can also be set into prong settings of various kinds, but the idea is the same – it’s the prongs going over the angle of the stone that creates the pressure that holds the stone in place.
