Turquoise

Physical Properties

Hardness: 5-6 Mohs; Color: Sky blue to apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually cryptocrystalline); Cleavage: Perfect but rarely seen; Specific Gravity: 2.6-2.9.

Formation & Geological History

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is commonly found in arid regions within volcanic or sedimentary host rocks. Most deposits are relatively young geologically (Cenozoic).

Uses & Applications

Primarily used as a gemstone for jewelry (cabochons, beads, inlay) and as an ornamental stone for carvings and decorative items.

Geological Facts

Turquoise has been mined for over 3,000 years; the name comes from the French 'turquois' meaning 'Turkish', as the stone first reached Europe via Turkey from Persian mines. It is the traditional birthstone for December.

Field Identification & Locations

Identify by its unique 'robin's egg' blue color and dark spider-web-like matrix of host rock (often limonite or sandstone). Commonly found in the Southwestern US (Arizona, Nevada), Iran, China, and Egypt. Collectors look for uniform color and absence of fractures.

Identified on: 4/27/2026

Mode: Standard