mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous (glassy); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, to deep reddish-purple
Luster: Vitreous (glassy)

Identified March 27, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or volcanic geodes when silica-rich water precipitates in cavities. The purple color results from irradiation of trivalent iron (Fe3+) impurities within the quartz lattice. Most commercial deposits are found in basaltic rocks millions of years old.

Uses & applications

Primary use is in jewelry as a gemstone (faceted or cabochon) and in ornamental carvings. Large geodes are highly sought after by mineral collectors for home decor and holistic practices.

Geological facts

Amethyst is the birthstone for February. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was historically believed to protect the wearer from drunkenness.

Field identification & locations

Identify by its distinctive purple color and quartz-like hardness (won't be scratched by a steel knife). Commonly found in Brazil, Uruguay, Zambia, and Ontario. In the field, look for hexagonal crystal points often growing inward in hollow rock cavities (geodes).

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