gemstone

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale. Color: pale violet to purple. Luster: vitreous (glassy). Crystal structure: trigonal/hexagonal. Cleavage: none, conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: pale violet to purple
Luster: vitreous (glassy)

Identified July 23, 2026More gemstone →

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Physical properties

Hardness: 7 on Mohs scale. Color: pale violet to purple. Luster: vitreous (glassy). Crystal structure: trigonal/hexagonal. Cleavage: none, conchoidal fracture. Specific gravity: 2.65.

Formation & geological history

Forms inside volcanic cavities (geodes) or hydrothermal veins when silicon dioxide crystallizes from iron-rich hydrothermal fluids at low to moderate temperatures.

Uses & applications

Widely used in jewelry, lapidary art, gemstone collecting, and ornamental carvings.

Geological facts

The purple color comes from trace amounts of iron irradiation in the crystal structure. Ancient Greeks believed amethyst could prevent drunkenness, deriving its name from 'amethystos' meaning 'not intoxicated'.

Field identification & locations

Identified by its purple coloration, hardness of 7 (scratches glass, cannot be scratched by steel), glassy luster, and conchoidal fracture. Commonly found in Brazil, Uruguay, Madagascar, Zambia, and Russia.

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