mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale), Color: Sky blue to green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (usually massive), Specific gravity: 2.6-2.9

Identified May 14, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs scale), Color: Sky blue to green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (usually massive), Specific gravity: 2.6-2.9

Formation & geological history

A secondary mineral formed by the percolation of acidic aqueous solutions through preexisting minerals containing copper, aluminum, and phosphorus in arid environments. Often found in weathered volcanic or sedimentary host rocks.

Uses & applications

Primarily used as a gemstone for jewelry, decorative carvings, and inlay work. Historically used for amulets and talismans.

Geological facts

Turquoise is one of the oldest gemstones in history, used by Egyptians since 3000 BC. The name comes from the French word 'turquois' for 'Turkish', as the gemstone was first imported to Europe through Turkey.

Field identification & locations

Identified by its unique blue-green color and vein-like 'matrix'. Commonly found in the Southwestern United States, China, Iran, and Mexico. For identification, look for the waxy luster and the presence of a dark brown or black limonite matrix.