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 sub-vitreous, Crystal structure: Triclinic (usually microcrystalline), Cleavage: Perfect but rarely seen, Specific gravity: 2.6-2.9

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

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

Uses & applications

Primarily used as a gemstone for jewelry and ornamental carvings. Historically significant for decorative arts and amulets in many global cultures.

Geological facts

Turquoise is one of the oldest gemstones used by humans, dating back to 3000 BC in Ancient Egypt. Its name comes from the French 'turquois', meaning 'Turkish', as it was first brought to Europe through Turkey from Persian mines.

Field identification & locations

Identify by its unique 'robin egg blue' color and frequent presence of dark veins (matrix). It is opaque and relatively soft. Major deposits are found in Iran, Southwestern USA, China, and Egypt. Collectors look for uniform color and high density.

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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)]

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Epidote

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

mineral