mineral

Amethyst Quartz (Amethyst Geode)

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Purple to violet due to irradiation of trivalent iron; Luster: Vitreous/Glassy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Purple to violet due to irradiation of trivalent iron
Luster: Vitreous/Glassy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings inside volcanic rock cavities (geodes). As mineral-rich hot water cools, crystals grow inward. Major deposits range from the Cretaceous period to more recent geological ages.

Uses & applications

Primarily used in jewelry (as a semi-precious gemstone), ornamental decor, lapidary arts, and by mineral collectors. It is also historically associated with spiritual practices and basalt-based industrial geode extraction.

Geological facts

Amethyst was considered a 'cardinal gem' or one of the most valuable minerals until large deposits were found in Brazil in the 18th century. Its name comes from the Greek 'amethystos', meaning 'not intoxicated', due to a belief it prevented drunkenness.

Field identification & locations

Identify in the field by its distinct purple hue and prismatic hexagonal crystals. Common locations include the Rio Grande do Sul region in Brazil, Artigas in Uruguay, and parts of Arizona, USA. It is often found within a basaltic or agate-lined outer shell.

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