mineral

Carborundum (Silicon Carbide)

Silicon Carbide (SiC) / Moissanite (natural form)

Hardness: 9–9.5 (Mohs scale), Color: iridescent black, green, or blue with rainbow highlights, Luster: adamantine to metallic, Crystal structure: hexagonal/trigonal, Cleavage: poor/none, Specific gravity: 3.21

Hardness: 9–9

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

While rare natural Moissanite occurs in meteorites and mantle-derived rocks, most specimens like the one pictured are man-made. They are created in electric resistance furnaces using the Acheson process, which fuses silica sand and carbon at temperatures between 1,600 and 2,500 °C.

Uses & applications

Used extensively as an industrial abrasive (sandpaper, grinding wheels), in semiconductor electronics, bulletproof vests, and as a diamond simulant in jewelry (Moissanite).

Geological facts

It is nearly as hard as a diamond. The iridescent 'rainbow' effect is caused by a thin layer of silicon dioxide that forms on the surface, creating thin-film interference similar to oil on water.

Field identification & locations

Identify by its extreme hardness, jagged crystalline structure, and distinct rainbow iridescence. It is rarely found in the field naturally; most specimens are found in rock shops or industrial sites. Its high thermal conductivity and hardness are key identifiers.

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