mineral

Amethyst (Rough Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender due to iron impurities and gamma irradiation; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous (glassy)

Identified July 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and basaltic geodes. The purple color is a result of irradiation of trivalent iron impurities (Fe3+) in the quartz structure. These crystals can range from a few million to hundreds of millions of years old.

Uses & applications

Primary use is in jewelry, lapidary arts, and as a popular collector's mineral. Higher quality specimens are faceted into gemstones, while lower quality stones are tumbled or carved.

Geological facts

Amethyst was considered one of the five cardinal gemstones until large deposits were found in Brazil. Its name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to protect its owner from drunkenness.

Field identification & locations

Identify by its characteristic purple color, hexagonal crystal habit (if terminations are present), and lack of cleavage. Common in Brazil, Uruguay, Zambia, and parts of the United States like Arizona.