mineral

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

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

Hardness: 5-6 (Mohs scale)
Color: Sky blue to blue-green
Luster: Waxy to sub-vitreous

Identified May 13, 2026More mineral →

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Physical properties

Formation & geological history

A secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals, specifically copper and aluminum-rich rocks in arid environments.

Uses & applications

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

Geological facts

Turquoise is one of the oldest known gemstones, used by Ancient Egyptians as early as 3000 BCE. Its name comes from the French 'turquois', meaning 'Turkish', as the stone initially reached Europe through Turkey.

Field identification & locations

Identify by its unique 'robin's egg' blue color and often a dark spiderweb-like matrix (veining). Commonly found in the Southwestern USA (Arizona, Nevada), Iran, and China. Collectors should look for vibrancy of color and hardness to distinguish from dyed howlite or magnesite.