mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale); Color: Sky blue to blue-green; Luster: Waxy to subvitreous; Crystal structure: Triclinic; Cleavage: Good to perfect (though rarely seen in massive specimens); Specific gravity: 2.6–2.9.

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

Identified June 7, 2026More mineral →

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Physical properties

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, occurring as veins or crusts in altered volcanic rocks.

Uses & applications

Primarily used as a gemstone for jewelry (beads, cabochons, carvings) and as an ornamental stone. It has significant cultural and decorative value in many indigenous societies.

Geological facts

Turquoise is one of the oldest gemstones in human history, used by Egyptians as far back as 3000 BCE. The 'matrix' seen in many stones is actually remnants of the host rock, such as limonite (brown) or manganese oxide (black).

Field identification & locations

Identify by its sky-blue to robin's egg blue color and waxy luster. In the field, look for thin veins in highly altered, aluminum-rich rocks in arid climates like the Southwestern US, Iran, or China.