Diamond Cutting Dops
The diamond is clamped into place, or sometimes bound by molten and cooled lead, in a special holder, commonly called a "dop". The cutter has an assortment of dops to choose from, depending on the section of the stone he is working on. There is also an assortment of small pots which are inserted into the dop to fit the size and shape of the diamond. The dop is then fixed into a holding tool called a "tang". Tangs vary in configuration and material, starting with the older style wood-and-copper stalk tangs which many of the old timers still use. This style of dop and tang is controlled manually by the cutter bending an annealed copper stalk attached to the base of the dop, to obtain the angle and straightness of the facet being fashioned.
The semi-automatic tang still allows great flexibility and fine cutting, but instead of bending a copper stalk to achieve the facet shape, two adjustment knobs are used, one for angle and the other for straightness. The fully automatic machines used in Russia, Thailand and India are capable of doing very precise work as well.