Boron carbide, also known as black diamond, is an inorganic substance with a chemical formula of B4C, usually gray-black micropowder. It is one of the three hardest materials known (second only to diamond and cubic boron nitride). It is used in gem grinding polishing tankarmor, bulletproof vests and many industrial applications. Its Mohs hardness is about 9.6

boron carbide is produced by high temperature smelting boric aid and carbon materails in electric furnaces.