Silicon carbide (SiC), also known as carborundum, is a compound of silicon and carbon with chemical formula SiC.   It occurs innature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as anabrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used inapplicationsrequiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Electronicapplications of silicon carbide as light-emitting diodes (LEDs) and detectorsin early radios were first demonstrated around 1907. Today SiC is used in semiconductor electronics applications that are high-temperature, high-voltage or both. Large single crystalsof silicon carbide can be grown by the Lely method; they can be cut into gems known as synthetic moissanite. Silicon carbidewith high surface area can be produced from SiO2 contained in plant material.