mineral

Silicon Carbide (Carborundum)

Silicon Carbide (SiC)

Hardness: 9-9.5 (Mohs scale); Color: Black to dark green with iridescent metallic highlights; Luster: Submetallic to adamantine; Crystal structure: Trigonal or hexagonal; Cleavage: None.

Hardness: 9-9
Color: Black to dark green with iridescent metallic highlights
Luster: Submetallic to adamantine

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 9-9.5 (Mohs scale); Color: Black to dark green with iridescent metallic highlights; Luster: Submetallic to adamantine; Crystal structure: Trigonal or hexagonal; Cleavage: None.

Formation & geological history

While a extremely rare natural form called Moissanite exists in meteorites, the specimen shown is synthetic. It is produced by the Acheson process, where silica sand and carbon are reacted in an electric furnace at high temperatures (up to 2500 degrees Celsius).

Uses & applications

Commonly used as an abrasive (sandpaper, cutting tools), in high-temperature ceramics, semiconductor electronics, and as decorative display specimens due to its iridescence.

Geological facts

It is one of the hardest known substances, second only to diamond and boron nitride. The iridescent 'rainbow' effect on the surface is caused by a thin layer of silicon dioxide that forms when it is exposed to air.

Field identification & locations

In a lab/market setting, it is identified by its extreme hardness, glittering black crystals, and rainbow sheen. It is rarely found in the field naturally; most specimens in collections are industrial byproducts.