Amethyst

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

Formed in igneous or metamorphic rock cavities (geodes) when silica-rich hydrothermal fluids precipitate. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities. Formation can occur across many geological periods.

Uses & Applications

Primary use is in jewelry and lapidary arts as a gemstone. It is also used in decorative ornaments and is highly popular as a specimen for mineral collectors.

Geological Facts

Amethyst was once considered one of the five cardinal gemstones alongside diamonds and rubies until large deposits were found in Brazil. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated'.

Field Identification & Locations

Identify by its hexagonal crystal habit, 7 hardness (it will scratch glass), and distinct purple zoning. Common locations include Brazil, Uruguay, Zambia, and Ontario, Canada.

Identified on: 4/15/2026

Mode: Standard