Amethyst Geode

Physical Properties

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

Formation & Geological History

Formed in gas cavities (vugs) in volcanic rocks like basalt. Hydrothermal fluids rich in silica deposit crystals over long periods. Commonly formed during the Cenozoic era.

Uses & Applications

Used primarily in jewelry, home decor, metaphysical practices, and as a popular collector specimen.

Geological Facts

The purple color comes from irradiation of trivalent iron (Fe3+) in the quartz structure. Amethyst was once considered one of the 'Cardinal Gems' alongside diamond and ruby.

Field Identification & Locations

Identify by its hexagonal crystal points and purple hue within a rocky shell. Large deposits are found in Brazil and Uruguay. Collectors look for deep 'Siberian' purple color and clarity.

Identified on: 5/3/2026

Mode: Standard