mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (tumbled/polished in image); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple to violet
Luster: Vitreous (glassy)

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins and geodes, typically when silica-rich fluids cool in cavities within igneous rocks. Its purple color is caused by natural irradiation of trace iron impurities.

Uses & applications

Primary use in jewelry, lapidary arts, and as decorative gemstone specimens for collectors. Used historically as an amulet to prevent intoxication.

Geological facts

Amethyst was considered one of the 'Cardinal Gems' until large deposits were found in Brazil in the 1700s. Its name comes from the Greek 'amethystos', meaning 'not drunken'.

Field identification & locations

Identify in the field by its purple hue and ability to scratch glass (hardness 7). Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors should look for deep purple color and high clarity.

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