mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale), Color: Sky-blue to apple-green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (usually massive), Cleavage: Perfect (rarely seen), Specific Gravity: 2.6-2.9

Identified June 27, 2026More mineral →

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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 massive), Cleavage: Perfect (rarely seen), 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. It is a secondary mineral usually found in arid regions within volcanic rocks or sedimentary phosphate deposits.

Uses & applications

Primarily used as a gemstone in jewelry (cabochons, beads, and inlay work) and for decorative ornamental carvings. Also a highly sought-after mineral for gemstone collectors.

Geological facts

Turquoise is one of the oldest gemstones in human history, used by Ancient Egyptians as early as 3000 BCE. The name is derived from the French 'turquois' meaning 'Turkish', as it first reached Europe via Turkey.

Field identification & locations

Identify in the field by its distinct robin-egg blue or green color and waxy appearance. Often found in veinlets or crusts. Common locations include the Southwestern US (Arizona, Nevada), Iran, and China. Collectors should look for 'matrix' patterns of host rock within the specimen.