Amethyst (Rough Quartz)

Physical Properties

Hardness: 7 (Mohs scale); Color: Pale violet to deep purple with white quartz matrix; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & Geological History

Formed in hydrothermal veins or as linings inside volcanic geodes. The purple color is caused by trace amounts of trivalent iron and irradiation from various sources in the core rock.

Uses & Applications

Used primarily in jewelry, lapidary arts, and as a popular collector's specimen. It is the birthstone for February and used for ornamental carving and decorative display.

Geological Facts

Amethyst was considered a 'Precious Stone' until the discovery of large deposits in Brazil in the 19th century. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', due to a belief it protected its owner from drunkenness.

Field Identification & Locations

Identify in the field by its distinct conchoidal fracture, hardness (it will scratch glass), and purple coloration. Commonly found in Brazil, Uruguay, Madagascar, and Arizona. Collectors should look for rich, uniform color for higher value.

Identified on: 4/22/2026

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