mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 on Mohs scale; Color: Pale lavender to deep royal purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (often found as druzy clusters); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Pale lavender to deep royal purple
Luster: Vitreous (glassy)

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as linings inside volcanic geodes. The purple color results from irradiation of trivalent iron (Fe3+) within the quartz structure. These specimens are often millions of years old, commonly found in Cretaceous or Jurassic age basaltic layers.

Uses & applications

Primary use is in jewelry (faceted gemstones/cabochons), ornamental decor (geodes, cathedrals), and as a popular specimen for mineral collectors. Historically used in drinking vessels to supposedly prevent intoxication.

Geological facts

Amethyst was considered one of the five cardinal gemstones until large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'. It is the birthstone for February.

Field identification & locations

Identify in the field by its distinct purple hue and hexagonal crystal terminations. Commonly found in Brazil, Uruguay, Zambia, and Canada. To identify, look for crystal clusters on a host rock (agate or basalt) and check that it can scratch glass but not topaz.

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