Amethyst (Quartz variety)

Physical Properties

Hardness: 7 (Mohs scale), Color: light to dark purple/violet, Luster: Vitreous, Crystal structure: Trigonal (hexagonal prisms), Cleavage: Indistinct/Conchoidal fracture, Specific gravity: 2.65

Formation & Geological History

Formed in hydrothermal veins and geodes. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities within the crystal structure. It is found in igneous host rocks like basalt or rhyolite and sometimes in metamorphic rocks.

Uses & Applications

Major use in jewelry (faceting, cabochons, beads). Highly popular as ornamental specimens for mineral collectors and decoration. Historically used as decorative hilts for weapons and amulets.

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', as it was believed to protect the wearer from drunkenness.

Field Identification & Locations

Identify in the field by its characteristic purple hue, 6-sided prism shape with pyramidal terminations, and its ability to scratch glass but not topaz. Commonly found in Brazil, Uruguay, Zambia, and the Lake Superior region of North America.

Identified on: 4/13/2026

Mode: Standard