mineral
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)
AI-generated identification · may be incorrectHardness: 5-6 (Mohs scale), Color: Sky blue to apple green, Luster: Waxy to subvitreous, Crystal Structure: Triclinic (usually cryptocrystalline), Specific Gravity: 2.6-2.9.
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Physical properties
Hardness: 5-6 (Mohs scale), Color: Sky blue to apple green, Luster: Waxy to subvitreous, Crystal Structure: Triclinic (usually cryptocrystalline), Specific Gravity: 2.6-2.9.
Formation & geological history
Secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Commonly found in arid regions within volcanic rocks or sedimentary phosphate deposits.
Uses & applications
Primarily used as a gemstone in jewelry (cabochons, beads) and for ornamental carvings. Occasionally used in industrial pigments.
Geological facts
Turquoise is one of the oldest known gemstones, used by Ancient Egyptians and Persians. The name comes from the French 'turquois' meaning Turkish, as it was first brought to Europe through Turkey.
Field identification & locations
Identify by its unique 'robin's egg' blue color and dark matrix veins (often limonite or manganese oxide). Found in Iran, Southwestern USA, China, and Egypt. Collectors look for uniform color and absence of treatment.
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous