mineral
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)
AI-generated identification · may be incorrectHardness: 5-6 Mohs. Color: Sky-blue to apple-green. Luster: Waxy to subvitreous. Crystal structure: Triclinic (usually occurs as massive/cryptocrystalline). Specific gravity: 2.6-2.9.
- Hardness
- 5-6 Mohs
- Color
- Sky-blue to apple-green
- Luster
- Waxy to subvitreous
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Physical properties
Hardness: 5-6 Mohs. Color: Sky-blue to apple-green. Luster: Waxy to subvitreous. Crystal structure: Triclinic (usually occurs as massive/cryptocrystalline). Specific gravity: 2.6-2.9.
Formation & geological history
Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Often found in arid regions within volcanic rocks or sedimentary phosphate-bearing rocks.
Uses & applications
Primarily used as a gemstone in jewelry, decorative carvings, and as a highly sought-after collector mineral.
Geological facts
Turquoise is one of the oldest known gemstones, used by Ancient Egyptians and Persians for over 5,000 years. The word 'turquoise' comes from the French for 'Turkish', as it first reached Europe via Turkey from Persian mines.
Field identification & locations
Identify in the field by its distinct blue-green color, lack of transparency, and association with host rocks like Limonite. Common in the Southwestern US (Arizona, Nevada), Iran, and China.
