mineral

Turquoise

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

Hardness: 5-6 (Mohs), Color: Sky blue to apple green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (rarely occurs as crystals), Specific Gravity: 2.6-2.9

Identified May 24, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs), Color: Sky blue to apple green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (rarely occurs as crystals), Specific Gravity: 2.6-2.9

Formation & geological history

A secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing copper minerals. Typically found in arid regions in veins and crusts.

Uses & applications

Primarily used as a gemstone for jewelry and ornamental carvings. Historically used for amulets and decorative inlays in weapons and architecture.

Geological facts

Turquoise is one of the oldest gemstones used by humans, with historical mines in the Sinai Peninsula dating back to 5000 BC. It is the traditional birthstone for December.

Field identification & locations

Identified by its distinctive robin's egg blue color and waxy appearance. Often found in copper mining districts such as the American Southwest, Iran, and China. Collectors look for 'matrix' (host rock veins) within the stone.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic