mineral

Turquoise

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

Hardness: 5-6 Mohs. Color: Sky blue to blue-green. Luster: Waxy to subvitreous. Crystal Structure: Triclinic (usually cryptocrystalline). Cleavage: Perfect, but rarely visible. Specific Gravity: 2.6-2.9.

Hardness: 5-6 Mohs
Color: Sky blue to blue-green
Luster: Waxy to subvitreous

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the percolation of meteoric water through copper-bearing aluminum-rich rock. Secondary mineral in the oxidation zones of copper deposits, often in arid climates. Typically found in volcanic or sedimentary host rocks.

Uses & applications

Primarily used in jewelry, ornamental carvings, and lapidary arts. Historically used as a pigment and for cultural talismans. High-grade specimens are highly valued by collectors.

Geological facts

Turquoise has been mined for over 3,000 years; the Egyptians used it in grave goods for pharaohs. It is one of the world's oldest known gemstones and the birthstone for December.

Field identification & locations

Identified by its distinctive blue-green color and waxy appearance. Often found in hydrothermal veins in arid regions like the SW United States, Iran, and China. Collectors should watch for 'stabilized' vs 'natural' versions.

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