a white powder, BN, formed by heating boron in nitrogen. In its ordinary form, it has a structure of stacked layers of hexagonal rings, very similar to that of graphite, and is used as a refractory electrical insulator.
The sample is held in crucibles made from alumina, boron nitride, or graphite.
The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride.
British Dictionary definitions for boron nitride
a white inert crystalline solid existing both in a graphite-like form and in an extremely hard diamond-like form (borazon). It is used as a refractory, high temperature lubricant and insulator, and heat shield. Formula: BN