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 cryptocrystalline/massive), Cleavage: Perfect (rarely seen), Specific Gravity: 2.6-2.9

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals; commonly found in arid regions within volcanic or sedimentary host rocks.

Uses & applications

Primarily used as a gemstone in jewelry (cabochons, beads, inlay) and for ornamental carvings. Highly valued in Native American and Persian cultural artifacts.

Geological facts

Turquoise is one of the oldest known gemstones, mined by Ancient Egyptians as early as 3000 BCE. Its name comes from the French 'turquois' meaning 'Turkish', as it was historically brought to Europe through Turkey.

Field identification & locations

Identify in the field by its distinct robin's-egg blue or green color and waxy appearance; it often contains a 'matrix' of brown limonite or black manganese oxide. Key locations include the Southwestern USA (Arizona, Nevada), Iran, and China.

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