gemstone

Turquoise

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

Sky-blue to greenish-blue color with a waxy to sub-vitreous luster; Hardness: 5-6 on the Mohs scale; Crystal structure: Triclinic (rarely well-formed, usually microcrystalline); Cleavage: Perfect in two directions but rarely seen; Specific gravity: 2.6-2.9; Often features brown or black host rock matrix veining.

Hardness: 5-6 on the Mohs scale

Identified July 24, 2026More gemstone →

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Physical properties

Formation & geological history

Secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing copper-bearing and aluminum-rich minerals in arid regions.

Uses & applications

Extensively used as an ornamental gemstone, in traditional Native American and Middle Eastern jewelry, cabochons, carvings, and as a popular mineral collector specimen.

Geological facts

Turquoise is one of the oldest gemstones known to humanity, mined by Ancient Egyptians as early as 3000 BCE. Its name derives from the Old French 'turquois', meaning 'Turkish', as the gemstone was first imported into Europe via Turkey.

Field identification & locations

Identified by its signature robin's-egg blue color, matrix patterns, and soft waxy luster. Commonly found in dry, arid climates such as the Southwestern United States (Arizona, Nevada, New Mexico), Iran, China, Sinai Peninsula, and Chile.

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