mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

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

Identified May 16, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is typically found in arid climates within volcanic or sedimentary host rocks.

Uses & applications

Primarily used in jewelry (beads, cabochons, inlays) and as an ornamental stone. Significant cultural use in Native American and Persian artworks.

Geological facts

Turquoise is one of the world's oldest gemstones, used by Ancient Egyptians as early as 3000 BCE. Its name comes from the French 'turquois' meaning Turkish, as it first reached Europe via Turkey.

Field identification & locations

Identify by its distinct blue-green hue and 'matrix' (web-like patterns of host rock). Often found in the Southwestern US, Iran, China, and Egypt. Collectors should look for natural, untreated specimens with deep color.