Amethyst (Tumbled)

Physical Properties

Hardness: 7 (Mohs scale); Color: Pale violet to deep purple (due to irradiation and iron); Luster: Vitreous/glassy; Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed in hydrothermal veins or as linings in volcanic geodes (vugs). The purple color results from the irradiation of trivalent iron (Fe3+) in the quartz crystal structure.

Uses & Applications

Predominantly used for jewelry, home decor, and as a popular specimen for mineral collectors. Historically believed to prevent intoxication.

Geological Facts

Amethyst was considered one of the 'cardinal gems' until the 18th century, when large deposits were found in Brazil and its value dropped. The name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field Identification & Locations

Identify by its distinctive purple color and lack of cleavage. In the field, look for hexagonal prisms with pyramidal terminations within volcanic rock cavities. Found globally in Brazil, Uruguay, and Africa.

Identified on: 4/29/2026

Mode: Standard