mineral

Silicon

Crystalline Silicon (Si)

Hardness: 7 Mohs; Color: Metallic silver-grey to bluish-black; Luster: Submetallic to vitreous; Crystal structure: Cubic (Diamond cubic); Cleavage: Perfect octahedral; Specific gravity: 2.33

Hardness: 7 Mohs
Color: Metallic silver-grey to bluish-black
Luster: Submetallic to vitreous

Identified June 2, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 Mohs; Color: Metallic silver-grey to bluish-black; Luster: Submetallic to vitreous; Crystal structure: Cubic (Diamond cubic); Cleavage: Perfect octahedral; Specific gravity: 2.33

Formation & geological history

While silicon is the second most abundant element in the Earth's crust, pure crystalline specimens like this are almost always synthetic, produced via the reduction of high-purity silica in electric arc furnaces.

Uses & applications

Primary component of semiconductors, solar cells, microchips, and various electronic components. Also used as an alloying agent in aluminum and steel production.

Geological facts

Pure silicon is a semiconductor, meaning its electrical conductivity is between that of a metal and an insulator. It was first isolated as a pure element in 1824 by Jöns Jacob Berzelius.

Field identification & locations

Identify by its light weight (low density) relative to its metallic appearance, brittle texture, and characteristic bluish-silver sheen. It will scratch glass but is very fragile.