mineral

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Hardness: 5-6 (Mohs scale); Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually cryptocrystalline); Cleavage: Perfect (rarely seen due to massive form); Specific Gravity: 2.6-2.9

Hardness: 5-6 (Mohs scale)
Color: Sky blue to apple green
Luster: Waxy to subvitreous

Identified March 2, 2026More mineral →

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Physical properties

Formation & geological history

Formed through secondary precipitation by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals like copper sulfides and feldspars. Found mainly in arid regions within volcanic or sedimentary host rocks.

Uses & applications

Primary use is in the jewelry and ornamental arts industry. It is highly valued for cabochons, beads, and carvings. Lower quality material is sometimes used in industrial architectural mosaics.

Geological facts

Turquoise is one of the oldest gemstones in history, used by Egyptians since 3000 BCE and revered by Native American tribes. Its name comes from the French 'turquois' meaning Turkish, as the stone originally reached Europe via Turkey.

Field identification & locations

Identify by its unique 'robin's egg' blue and characteristic dark spider-web matrix (limonite or sandstone inclusions). Found in Iran, Southwest USA, China, and Mexico. Collectors should look for uniform color and density; avoid 'chalk' turquoise that has been plastic-stabilized.

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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