mineral

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale), Color: Sky blue to blue-green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (usually massive/cryptocrystalline), Cleavage: None visible in massive forms, Specific gravity: 2.6-2.9

Identified May 16, 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 typically found in arid regions as veins or crusts within altered volcanic rocks or sedimentary environments containing phosphorus compounds.

Uses & applications

Primarily used in jewelry for cabochons, beads, and inlay. It is also used in decorative ornaments and is a highly valued collector's mineral.

Geological facts

Turquoise has been mined since at least 6000 BCE in Egypt. It is known as the 'stone of the sky' in many indigenous cultures and is the traditional birthstone for December.

Field identification & locations

Identify by its characteristic robin-egg blue color and waxy luster. In the field, look for it in arid, copper-rich regions such as the Southwestern United States, Iran, and China. Collectors should look for 'matrix' patterns (remnants of host rock) to verify natural origin.

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Arenite (SiO2 based)

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Epidote

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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)

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