mineral

Turquoise

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

Hardness: 5-6 (Mohs), Color: Blue to green, Luster: Waxy to sub-vitreous, Crystal Structure: Triclinic (usually cryptocrystalline), Specific Gravity: 2.6-2.9.

Identified April 6, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs), Color: Blue to green, Luster: Waxy to sub-vitreous, Crystal Structure: Triclinic (usually cryptocrystalline), Specific Gravity: 2.6-2.9.

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Usually found in arid climates within volcanic or sedimentary host rocks.

Uses & applications

Primarily used as a gemstone in jewelry, decorative carvings, and as a collector's specimen. Historically used for amulets and dental inlays.

Geological facts

Turquoise is one of the oldest gemstones known to man, used by Egyptians as early as 3000 BCE. Its color comes from copper (blue) and iron or chrome (green).

Field identification & locations

Identify by its unique sky-blue to apple-green color and waxy luster. Look for 'matrix' (veins of host rock). Commonly found in the SW USA, Iran, and China. Collectors should check for stabilization treatments.

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