mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs); Color: Sky blue to blue-green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually massive/cryptocrystalline); Cleavage: Perfect (rarely seen)

Hardness: 5-6 (Mohs)
Color: Sky blue to blue-green
Luster: Waxy to subvitreous

Identified July 10, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs); Color: Sky blue to blue-green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (usually massive/cryptocrystalline); Cleavage: Perfect (rarely seen)

Formation & geological history

A secondary mineral formed by the action of percolating acidic solutions during the weathering and oxidation of pre-existing minerals, typically in arid volcanic or hydrothermal environments containing copper and phosphorus.

Uses & applications

Primarily used as a gemstone for jewelry, cabochons, beads, and inlay work. Highly valued for ornamental and spiritual purposes.

Geological facts

Turquoise is one of the oldest gemstones in history, used by Ancient Egyptians and Native American tribes. Many blue stones in the market are actually dyed Howlite or Magnesite meant to imitate turquoise.

Field identification & locations

Identified by its distinctive robin-egg blue color and dark matrix veins (limonite or manganese). In the field, look for it in arid regions near copper deposits. It is often porous and can be tested for dye using a cotton swab with acetone.