mineral

Turquoise (set in silver jewelry)

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Hardness: 5-6 (Mohs scale), Color: Sky blue to apple green, Luster: Waxy to subvitreous, Crystal Structure: Triclinic (usually cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.9.

Identified March 20, 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 minerals. It is a secondary mineral usually found in arid regions within volcanic or sedimentary host rocks.

Uses & applications

Primarily used in jewelry (cabochons, beads, and inlay) and ornamental carvings. It has been a prized gemstone for over 3,000 years.

Geological facts

Turquoise was one of the first gemstones ever mined; the ancient Egyptians mined it in the Sinai Peninsula as far back as 3000 BCE. Its name comes from the French 'turquois' meaning 'Turkish', as it first reached Europe via Turkey.

Field identification & locations

Identify by its unique blue-green color and 'matrix' (web-like veins of host rock). Often found in copper-rich deposits in the Southwestern USA, China, and Iran. Collectors should check for stabilization treatments or dye.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

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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

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Epidote

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

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