mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

AI-generated identification · may be incorrect

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

Hardness: 7 on Mohs scale
Color: light to deep purple
Luster: Vitreous (glassy)

Identified April 29, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms inside igneous volcanic rocks (geodes) or hydrothermal veins when silica-rich water crystallizes over time. The purple color is caused by trace amounts of iron radiated by natural radioactivity in the surrounding rock.

Uses & applications

Primarily used in jewelry, lapidary arts, and as a popular collector's mineral. High-quality specimens are faceted into gemstones.

Geological facts

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

Field identification & locations

Identify by its purple hue, 6-sided crystal habit (if points are present), and its ability to scratch glass. Commonly found in Brazil, Uruguay, Zambia, and Ontario, Canada.