gemstone

Turquoise

Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

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

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

Identified July 17, 2026More gemstone →

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Physical properties

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

Formation & geological history

Formed as a secondary mineral by the action of percolating acidic solutions during the weathering and oxidation of pre-existing minerals, typically found in arid regions within volcanic rocks or phosphorus-rich sediments.

Uses & applications

Primarily used as an ornamental stone and gemstone in jewelry, such as rings, necklaces, and Southwestern-style silver work. Historically used for talismans and amulets.

Geological facts

Turquoise is one of the oldest gemstones known to man, having been mined by Ancient Egyptians as early as 3200 BC. The name comes from the French 'turquois' meaning 'Turkish', as it first reached Europe via Turkey.

Field identification & locations

Identified by its distinctive robin's-egg blue to green color and waxy luster. In the field, look for it in vein-fillings or nodules in altered volcanic rock. Commonly found in Arizona, Nevada, Iran, and China.

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