Amethyst (Quartz)

Physical Properties

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

Formation & Geological History

Forms in hydrothermal veins and hollow cavities (geodes) within igneous rocks. The purple color is caused by irradiation of iron impurities within the crystal lattice.

Uses & Applications

Primarily used in jewelry (as a semi-precious gemstone), decorative carvings, lapidary arts, and as a popular specimen for mineral collectors.

Geological Facts

Amethyst is the birthstone for February. Ancient Greeks believed it could prevent intoxication; the word comes from the Greek 'amethystos', meaning 'not drunken'.

Field Identification & Locations

Identify in the field by its characteristic purple hue, 6-sided hexagonal prism terminations, and ability to scratch glass. Commonly found in Brazil, Uruguay, and parts of Arizona and Ontario.

Identified on: 4/15/2026

Mode: Standard