![Turquoise (Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]) — mineral](https://media.rockidentification.com/73f8afee-8a6e-4926-b9b4-21c6515d4b67-compressed.jpg)
mineral
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Hardness: 5-6 (Mohs scale); Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (rarely found in crystal form, usually cryptocrystalline masses); Cleavage: Perfect (rarely seen); Specific Gravity: 2.6-2.9.
- Hardness
- 5-6 (Mohs scale)
- Color
- Sky blue to apple green
- Luster
- Waxy to subvitreous
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Physical properties
Hardness: 5-6 (Mohs scale); Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (rarely found in crystal form, usually cryptocrystalline masses); Cleavage: Perfect (rarely seen); Specific Gravity: 2.6-2.9.
Formation & geological history
Formed as a secondary mineral by the action of percolating acidic solutions during the weathering and oxidation of pre-existing minerals (copper-bearing rocks) in arid climates. It often fills veins or occurs as crusts in volcanic rocks.
Uses & applications
Primarily used as a gemstone and ornamental stone in jewelry, carvings, and inlays. Especially significant in Native American, Persian, and Egyptian cultural artistry.
Geological facts
It is one of the oldest gemstones in human history, used by Egyptians as far back as 3000 BCE. The name comes from the French word 'turquois', meaning 'Turkish', as the stone first reached Europe through Turkish trade routes.
Field identification & locations
Identify by its unique 'robin's egg' blue color and dark spider-web-like veins (matrix) made of limonite or manganese oxide. Commonly found in the Southwestern USA (Arizona, Nevada), Iran, and China. In the field, look for sky-blue outcrops in weathered igneous rocks near copper deposits.
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![Green Apatite on Albite (Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]) — mineral](https://media.rockidentification.com/2391a63f-fb20-47d5-af9a-2035851eb32e-thumbnail.jpg)
Green Apatite on Albite
Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]
mineral
Epidote
Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)
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