gemstone

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 on the Mohs scale; Color: Characteristic robin's-egg blue, greenish-blue, to green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic; Cleavage: Perfect in one direction, good in another (rarely seen as crystals); Specific Gravity: 2.60-2.90

Hardness: 5-6 on the Mohs scale
Color: Characteristic robin's-egg blue, greenish-blue, to green
Luster: Waxy to subvitreous

Identified August 1, 2026More gemstone →

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Physical properties

Formation & geological history

Formed by the chemical action of descending water rich in copper and aluminum percolating through host rocks in arid to semi-arid regions.

Uses & applications

Widely used in jewelry, ornamental carvings, and inlay work.

Geological facts

Turquoise is one of the oldest gemstones in history, prized by ancient civilizations such as the Egyptians, Persians, and Native Americans for sacred amulets and jewelry.

Field identification & locations

Easily identified by its unique bright blue-to-green color and often webbed matrix pattern. Commonly mined in the southwestern United States, Iran, China, and Sinai.