mineral
Turquoise
CuAl6(PO4)4(OH)8·4H2O
Mohs hardness of 5 to 6; color ranges from bright blue to green-blue, often with dark brown, black, or grey web-like veins (matrix); luster ranges from waxy to sub-vitreous; crystal system is triclinic; specific gravity is 2.60-2.90.
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Physical properties
Mohs hardness of 5 to 6; color ranges from bright blue to green-blue, often with dark brown, black, or grey web-like veins (matrix); luster ranges from waxy to sub-vitreous; crystal system is triclinic; specific gravity is 2.60-2.90.
Formation & geological history
Forms as a secondary mineral in arid regions through the weathering and oxidation of pre-existing copper-bearing minerals, typically in weathered volcanic or sedimentary rocks containing aluminum and phosphorus.
Uses & applications
Widely used in jewelry, decorative carvings, inlay work, and as a collector's gemstone.
Geological facts
Turquoise is one of the world's most ancient gemstones, used by the Ancient Egyptians, Native Americans, and Persians as amulets, trade items, and royal jewelry.
Field identification & locations
Identified by its distinct robin's egg blue or greenish-blue color and characteristic dark matrix webbing. Found prominently in the Southwestern United States, Iran, China, and Egypt.
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