mineral

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified May 17, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins and hollow decorative cavities (geodes) within igneous rocks, particularly volcanic rocks like basalt. The color is caused by irradiation of iron impurities in quartz.

Uses & applications

Primarily used in jewelry (faceting and cabochons), crystal healing, and as decorative specimen pieces for collectors.

Geological facts

Until the 19th century, amethyst was as expensive as ruby and emerald until large deposits were found in Brazil. It is the birthstone for February and was once believed by ancient Greeks to prevent intoxication.

Field identification & locations

Look for hexagonal crystal forms, purple coloration that may be uneven or 'color zoned', and a lack of cleavage. Common in Brazil, Uruguay, Zambia, and Canada.