Because natural moissanite is extremely scarce, most silicon carbide is synthetic. Silicon carbide is used as an abrasive, as well as a semiconductor and diamond simulant of gem quality. The simplest process to manufacture silicon carbide is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between  and . Fine SiO particles in plant material (e.g. rice husks) can be converted to SiC by heating in the excess carbon from the organic material. The silica fume, which is a byproduct of producing silicon metal and ferrosilicon alloys, can also be converted to SiC by heating with graphite at .
The material formed in the Acheson furnace varies in purity, according to its distance from the graphite resistor heat source. Colorless, pale yellow and green crystals have the highest purity and are found closest to the resistor. The color changes to blue and black at greater distance from the resistor, and these darker crystals are less pure. Nitrogen and aluminium are common impurities, and they affect the electrical conductivity of SiC.
Pure silicon carbide can be made by the Lely process, in which SiC powder is sublimed into high-temperature species of silicon, carbon, silicon dicarbide (SiC), and   disilicon carbide (SiC) in an argon gas ambient at 2500 °C and redeposited into flake-like single crystals, sized up to 2 × 2 cm, at a slightly colder substrate. This process yields high-quality single crystals, mostly of 6H-SiC phase (because of high growth temperature).
A modified Lely process involving induction heating in graphite crucibles yields even larger single crystals of 4 inches (10 cm) in diameter, having a section 81 times larger compared to the conventional Lely process.
Cubic SiC is usually grown by the more expensive process of chemical vapor deposition (CVD) of silane, hydrogen and nitrogen. Homoepitaxial and heteroepitaxial SiC layers can be grown employing both gas and liquid phase approaches.
To form complexly shaped SiC,  preceramic polymers can be used as precursors which form the ceramic product  through pyrolysis at temperatures in the range 1000–1100 °C. Precursor materials to obtain silicon carbide in such a manner include polycarbosilanes, poly(methylsilyne) and polysilazanes. Silicon carbide materials obtained through the pyrolysis of preceramic polymers are known as polymer derived ceramics or PDCs. Pyrolysis of preceramic polymers is most often conducted under an inert atmosphere at relatively low temperatures. Relative to the CVD process, the pyrolysis method is advantageous because the polymer can be formed into various shapes prior to thermalization into the ceramic.
SiC can also be made into wafers by cutting a single crystal either using a diamond wire saw or by using a laser. SiC is a useful semiconductor used in power electronics.