mineral

Turquoise

Hydrated phosphate of copper and aluminium (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 microcrystalline), Cleavage: Perfect (rarely seen), Specific gravity: 2.6-2.9

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

A secondary mineral formed by the action of percolating acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Often found in arid regions within volcanic rocks or sedimentary environments. Geological age varies greatly by deposit.

Uses & applications

Predominantly used as a gemstone in jewelry (cabochons, beads, and carvings). Highly valued for aesthetic and ornamental purposes across many cultures.

Geological facts

Turquoise is one of the oldest known gemstones, used by Ancient Egyptians and Native American tribes for thousands of years. It is the birthstone for December.

Field identification & locations

Identify in the field by its distinct waxy luster and blue-green hue, often associated with limonite (brown) or quartz veins. Commonly found in Iran, Southwestern USA (Arizona, Nevada), and China. Look for its presence in copper-rich oxidation zones.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral