mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale), Color: Sky blue to blue-green, Luster: Waxy to subvitreous, Crystal structure: Triclinic, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.9

Identified May 24, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs scale), Color: Sky blue to blue-green, Luster: Waxy to subvitreous, Crystal structure: Triclinic, Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.9

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is a secondary mineral usually found in arid regions within volcanic rocks or sedimentary deposits containing copper.

Uses & applications

Primarily used as a gemstone in jewelry (beads, cabochons, inlays) and for ornamental decorative objects. Highly valued in indigenous Southwestern and Middle Eastern artistry.

Geological facts

Turquoise is one of the oldest gemstones used by humans, with a history dating back over 3,000 years to Ancient Egypt and the Persian Empire. It gets its blue color from copper and its green color from iron or aluminum.

Field identification & locations

Identify by its characteristic 'robin's egg' blue color and dark spider-web like veins (matrix) of host rock. Commonly found in Iran, Southwestern USA (Arizona, Nevada), China, and Mexico. Collectors should look for even color and density.