Amethyst

Silicon Dioxide (SiO2) with iron impurities

Rock Type: mineral

Amethyst

Physical Properties

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

Formation & Geological History

Formed in cavities (geodes) of igneous rocks, specifically basalt, or in hydrothermal veins. The purple color comes from irradiation of iron impurities within the quartz crystal lattice.

Uses & Applications

Primarily used as a gemstone in jewelry (rings, necklaces, earrings), as ornamental carvings, and it is a very popular specimen for mineral collectors.

Geological Facts

Amethyst was once considered as valuable as diamonds or rubies until large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field Identification & Locations

Identify by its distinct purple hue and 6-sided crystal habit when unpolished. It can be found globally with major deposits in Brazil, Uruguay, and Zambia. In the field, it is often found inside vugs or large rocky bubbles.

Identified on: 4/23/2026

Mode: Standard