mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7.0 on the Mohs scale. Color: Pale violet to deep purple. Luster: Vitreous (glassy). Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7
Color: Pale violet to deep purple
Luster: Vitreous (glassy)

Identified March 24, 2026More mineral →

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Physical properties

Hardness: 7.0 on the Mohs scale. Color: Pale violet to deep purple. Luster: Vitreous (glassy). Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Formed in igneous or metamorphic rocks as hydrothermally deposited crystals, typically within geodes or cavities in basalt. The purple hue is caused by irradiation of trivalent iron impurities. Specimens can range from thousands to millions of years old.

Uses & applications

Primary use is in jewelry as a semi-precious gemstone. Also used in decor, watchmaking, and highly valued by mineral collectors for its aesthetic crystal clusters.

Geological facts

Amethyst was considered a 'Cardinal Gem' until large deposits were found in Brazil. The name comes from the Ancient Greek word 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify in the field by its distinct purple color, 6-sided crystal shape ending in a pyramid, and the fact that it can scratch glass but cannot be scratched by a steel knife. Common locations include Brazil, Uruguay, and Zambia.

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