Amethyst Geode

Physical Properties

Hardness: 7 on Mohs scale; Color: Pale violet to deep purple; Luster: Vitreous (glassy); Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & Geological History

Formed in hollow cavities (vugs) of volcanic rocks through hydrothermal deposition. Silica-rich fluids precipitate crystals over millions of years. The purple color is caused by irradiation of trivalent iron impurities (Fe3+).

Uses & Applications

Used extensively in jewelry (faceted gemstones, beads), ornamental decorations, crystal healing practices, and as a popular specimen for mineral collectors.

Geological Facts

Amethyst was once considered a 'Cardinal Gem' and was as valuable as diamond or ruby until large deposits were discovered in Brazil in the 19th century. The name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field Identification & Locations

Identify by its characteristic purple color and hexagonal crystal terminations inside a rocky outer rind. Commonly found in Brazil, Uruguay, and Madagascar. Field identification involves checking hardness (scratches glass) and looking for color zoning.

Identified on: 5/3/2026

Mode: Standard