mineral

Amethyst (Quartz Cluster)

Silicon Dioxide (SiO2) with iron impurities

AI-generated identification · may be incorrect

Hardness: 7 on the Mohs scale. Color: Pale violet to deep purple. Luster: Vitreous (glass-like). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Pale violet to deep purple
Luster: Vitreous (glass-like)

Identified March 26, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale. Color: Pale violet to deep purple. Luster: Vitreous (glass-like). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins or cavities (geodes) when silica-rich water cools. The purple color is caused by trace amounts of iron and natural irradiation within the earth's crust. Most commercial deposits date from the Cretaceous period.

Uses & applications

Primary use is in jewelry (faceted gemstones, beads) and as decorative specimens for collectors or home decor. Historically used as a talisman for 'sobriety'.

Geological facts

The name comes from the Greek word 'amethystos', meaning 'not intoxicated'. Until the 18th century, it was considered a 'Cardinal Gem' and was as valuable as diamond or ruby until large deposits were found in Brazil.

Field identification & locations

Identify in the field by its distinct purple color, 6-sided prismatic crystals ending in a pyramid, and lack of cleavage. Often found in basaltic rocks in regions like Brazil, Uruguay, and Thunder Bay, Ontario.