Amethyst

Physical Properties

Hardness: 7 (Mohs scale), Color: light to deep purple, Luster: Vitreous, Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & Geological History

Forms in hollow geodes or cavities within igneous rocks. The purple color results from irradiation of iron impurities in the quartz structure. Most specimens range from late Mesozoic to Cenozoic geological eras.

Uses & Applications

Primary use is in jewelry (faceted gemstones, cabochons) and as decorative collector specimens (geodes/clusters). Historically used for amulets and drinking vessels.

Geological Facts

The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to protect its owner from drunkenness. It was once considered one of the five cardinal gemstones until large deposits were found in Brazil.

Field Identification & Locations

Identify by its distinct purple hue and crystal habit (six-sided prisms). Commonly found in Brazil, Uruguay, Zambia, and South Korea. Collectors should look for deep uniform color and lack of visible inclusions.

Identified on: 4/18/2026

Mode: Standard