mineral

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale); Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually cryptocrystalline); Cleavage: Perfect (rarely seen due to microcrystalline nature); Specific Gravity: 2.6-2.9

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

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals containing copper, aluminum, and phosphorus. Typically found in arid regions within volcanic rocks or sedimentary environments.

Uses & applications

Primarily used as a gemstone in jewelry (rings, necklaces, bracelets) and as an ornamental stone in carvings and inlays. It is highly valued for both its color and its historical significance in various cultures.

Geological facts

One of the oldest known gemstones, it was used by ancient Egyptians as early as 3000 BCE. The name comes from the French word 'turquois', meaning 'Turkish', as the stone originally reached Europe via Turkey from mines in Persia.

Field identification & locations

Identification includes its characteristic robin-egg blue color, waxy luster, and common presence of a matrix (host rock veins). Found in the Southwestern US, Iran, China, and Egypt. Collectors should watch for 'stabilized' or dyed fakes like howlite.