mineral

Amethyst Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/glassy, Crystal Structure: Trigonal/hexagonal, Cleavage: None/conchoidal fracture, Specific Gravity: 2.65

Identified June 20, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/glassy, Crystal Structure: Trigonal/hexagonal, Cleavage: None/conchoidal fracture, Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, typically occurring within geodes or cavities in volcanic rock. It forms when silica-rich hydrothermal fluids crystallize over millions of years, with its purple color resulting from irradiation and trace iron impurities.

Uses & applications

Primarily used in jewelry, as a decorative lapidary material, and highly valued for mineral collecting and alternative healing practices.

Geological facts

Until the discovery of large deposits in Brazil in the 19th century, amethyst was considered one of the 'Cardinal Gems' and was as expensive as diamonds and rubies. It is the birthstone for February.

Field identification & locations

Identify in the field by its distinct purple hue and its inability to be scratched by a steel knife. Common locations include Brazil, Uruguay, Madagascar, and the Lake Superior region of North America.