mineral

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Purple, violet, to pale lavender; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Purple, violet, to pale lavender
Luster: Vitreous/glassy

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, to pale lavender; Luster: Vitreous/glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins and volcanic cavities (geodes). The purple color is caused by irradiation of trivalent iron impurities (Fe3+) in the quartz structure. These can range from millions to billions of years old.

Uses & applications

Primary use is in jewelry, carvings, and as decorative collector specimens. Historically used for amulets and thought to prevent intoxication.

Geological facts

Amethyst was considered one of the 'Cardinal Gems' along with diamond and ruby until large deposits were found in Brazil in the 19th Century. The name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identify in the field by its distinct purple color, lack of cleavage, and ability to scratch glass. Commonly found in Brazil, Uruguay, Zambia, and Canada. Look for hexagonal crystal faces in volcanic host rocks.