mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

AI-generated identification · may be incorrect

Hardness: 7 Mohs; Color: Pale violet to deep purple; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None; Specific gravity: 2.65

Hardness: 7 Mohs
Color: Pale violet to deep purple
Luster: Vitreous

Identified July 20, 2026More mineral →

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Physical properties

Hardness: 7 Mohs; Color: Pale violet to deep purple; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None; Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and basaltic geodes. Secondary crystallization occurs when silica-rich water fills rock cavities over millions of years, with color resulting from irradiation of iron impurities in the quartz structure.

Uses & applications

Extensively used in jewelry (faceting, cabochons), ornamental decoration, and as a popular mineral for metaphysical collections and interior design.

Geological facts

Amethyst was considered a precious stone equal to diamonds until large deposits were discovered in Brazil in the 1700s. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.

Field identification & locations

Identify by purple hue, 6-sided prismatic crystals, and lack of cleavage. Found in basalt cavities in Brazil and Uruguay; also found in Arizona and Ontario. Use a scratch test (harder than glass) to confirm as quartz.