mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (often found as hexagonal prisms); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings within volcanic rock cavities (geodes). The purple color is caused by irradiation of trivalent iron (Fe3+) in the crystal structure. They can be found in rocks ranging from relative recent age back to billions of years old.

Uses & applications

Primary use is in jewelry (faceted gemstones, beads, and cabochons). Also popular as decorative mineral specimens, geodes for interior design, and historically used to prevent intoxication.

Geological facts

The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to protect its owner from drunkenness. It was once considered one of the five cardinal gems alongside diamonds, rubies, emeralds, and sapphires until large deposits were discovered in Brazil.

Field identification & locations

Identify in the field by its distinctive purple color, hardness (it will scratch glass and pocket knife steel), and lack of cleavage. Common locations include Brazil, Uruguay, Zambia, and South Korea.

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