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), Cleavage: Perfect (none seen in masses), Specific Gravity: 2.6-2.9

Identified April 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the infiltration of meteoric water (rainwater) through copper-bearing aluminous rock. It occurs in arid climates as a secondary mineral in altered volcanic rocks and hydrothermal deposits.

Uses & applications

Primarily used as an ornamental gemstone for jewelry (beads, cabochons), carvings, and historical decorative inlay.

Geological facts

Turquoise is one of the oldest known gemstones, used by Ancient Egyptians as early as 3000 BCE. Its color comes from copper (blue) and iron or chrome (green).

Field identification & locations

Identify by its unique 'robin egg blue' color and dark 'matrix' (the webbing pattern of the host rock). Often found in the Southwestern USA, Iran, and China. Collectors look for vibrant color and lack of chalkiness.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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