mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper aluminum phosphate)

AI-generated identification · may be incorrect

Hardness: 5-6 Mohs. Color: Sky-blue to turquoise green. Luster: Waxy to subvitreous. Crystal system: Triclinic (rarely found in distinct crystals, usually cryptocrystalline or massive). Specific gravity: 2.6-2.9.

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

Identified July 24, 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 alteration of pre-existing copper-bearing minerals in arid regions, often within hydrothermal copper deposits.

Uses & applications

Widely used as an ornamental gemstone, in jewelry (beads, cabochons, Native American silver inlay), and valued by mineral collectors.

Geological facts

Turquoise is one of the oldest known gemstones, used in ancient Egypt, Persia, and pre-Columbian Mesoamerica for over 3,000 years. Its name originates from the French 'turquois', meaning 'Turkish', because it reached Europe via Turkey.

Field identification & locations

Identified by its distinctive robin's-egg blue to greenish-blue color, opaque body, waxy luster, and dark brown or black vein-like matrix patterns. Commonly found in Iran, the Southwestern United States (Arizona, Nevada), China, and Egypt.