Turquoise (Green variety)

Hydrous phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Rock Type: mineral

Turquoise (Green variety)

Physical Properties

Hardness: 5-6 (Mohs), Color: Apple-green to forest-green, Luster: Waxy to sub-vitreous, Crystal structure: Triclinic (usually massive/cryptocrystalline), Cleavage: None/Perfect in rare crystals, 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 usually found in arid regions, filling veins and cavities in volcanics and sedimentary rocks.

Uses & Applications

Primarily used in jewelry as cabochons, carvings, and beads. Highly valued by collectors and indigenous cultures (e.g., Native American jewelry).

Geological Facts

While most people associate turquoise with blue, green turquoise is common and results from a higher iron content replacing aluminum in the structure. It has been mined for over 3,000 years in regions like Persia and the American Southwest.

Field Identification & Locations

Identify by its waxy luster, lack of cleavage, and often the presence of a 'matrix' (web-like patterns of host rock). Found in Southwestern USA, China, Iran, and Mexico. Collectors should look for smoothness and color density.

Identified on: 4/16/2026

Mode: Standard