mineral

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Hardness: 5-6 Mohs; Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually cryptocrystalline); Cleavage: Perfect but rarely seen; Specific Gravity: 2.6-2.9.

Hardness: 5-6 Mohs
Color: Sky blue to apple green
Luster: Waxy to subvitreous

Identified April 27, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is commonly found in arid regions within volcanic or sedimentary host rocks. Most deposits are relatively young geologically (Cenozoic).

Uses & applications

Primarily used as a gemstone for jewelry (cabochons, beads, inlay) and as an ornamental stone for carvings and decorative items.

Geological facts

Turquoise has been mined for over 3,000 years; the name comes from the French 'turquois' meaning 'Turkish', as the stone first reached Europe via Turkey from Persian mines. It is the traditional birthstone for December.

Field identification & locations

Identify by its unique 'robin's egg' blue color and dark spider-web-like matrix of host rock (often limonite or sandstone). Commonly found in the Southwestern US (Arizona, Nevada), Iran, China, and Egypt. Collectors look for uniform color and absence of fractures.