silicon carbide, chemical compound, SiC, that forms extremely hard, dark, iridescent crystals that are insoluble in water and other common solvents. Widely used as an abrasive, it is marketed under such familiar trade names as Carborundum and Crystolon. It is heat resistant, decomposing when heated to about 2,700°C; it is used in refractory materials, e.g., rods, tubes, firebrick, and in special parts for nuclear reactors. Very pure silicon carbide is white or colorless; crystals of it are used in semiconductors for high-temperature applications. Silicon carbide fibers, added as reinforcement to plastics or light metals, impart increased strength and stiffness. Silicon carbide is prepared commercially by fusing sand and coke in an electric furnace at temperatures above 2,200°C; a flux, e.g., sodium chloride, may be added to eliminate impurities. Silicon carbide was discovered (1891) by E. G. Acheson; early studies of it were made by Henri Moissan.