mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrous Phosphate of Copper and Aluminum)

AI-generated identification · may be incorrect

Hardness: 5-6 (Mohs scale); Color: Sky blue, blue-green, or apple-green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually microcrystalline); Cleavage: Perfect (rarely seen in massive forms); Specific Gravity: 2.6-2.9.

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

Identified March 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals such as copper and aluminum. It is primarily found in arid regions within volcanic or sedimentary host rocks.

Uses & applications

Predominantly used as a gemstone for jewelry, including rings, necklaces, and Southwestern-style silver work. It is also a popular collector's mineral and has been used for ornamental carvings and amulets for millennia.

Geological facts

Turquoise is one of the oldest known gemstones, used by Ancient Egyptians and Native Americans. High-quality specimens with 'spider web' matrix (black or brown veins) are highly prized. It is the traditional birthstone for December.

Field identification & locations

Identify in the field by its distinct robin's egg blue color and waxy appearance. Commonly found in the Southwestern USA (Arizona, Nevada), Iran, and China. Collectors should watch for 'stabilized' or dyed howlite imitations, often sold as 'Blue Howlite'.