mineral

Amethyst

Silicon dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous (glassy), Crystal system: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific gravity: 2.65

Identified July 14, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous (glassy), Crystal system: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or geodes within volcanic rocks when silica-rich fluids permeate cavities. The purple color is caused by irradiation of iron impurities in the quartz structure. Most specimens are from the Jurassic or Cretaceous periods.

Uses & applications

Predominantly used as a gemstone in jewelry, for decorative carvings, and as a popular mineral specimen for collectors. In industry, quartz is used for abrasive and glass-making purposes, though amethyst is rarely used for this due to its value as a gem.

Geological facts

Amethyst is the birthstone for February. The name comes from the Greek word 'amethystos,' meaning 'not intoxicated,' as ancient Greeks believed it could prevent drunkenness.

Field identification & locations

Identify by its characteristic purple color, hexagonal crystal habits (if present), and inability to be scratched by a steel knife. Commonly found in Brazil, Uruguay, Madagascar, and Russia. Collectors should look for deep, uniform color and clarity.