mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Hardness: 7 (Mohs scale), Color: light to deep purple, Luster: vitreous (glassy), Crystal System: hexagonal, Cleavage: none, Specific Gravity: 2.65

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: light to deep purple, Luster: vitreous (glassy), Crystal System: hexagonal, Cleavage: none, Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as linings in volcanic geodes. The purple color is caused by trace amounts of iron and natural irradiation over millions of years. Most large deposits are from the Cretaceous period.

Uses & applications

Primary use is in jewelry, lapidary art, and as a popular collector's specimen. In industry, quartz is used for abrasive and glassmaking, though colored varieties like amethyst are usually reserved for aesthetics.

Geological facts

Amethyst is the birthstone for February. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated', as ancient Greeks believed it could prevent drunkenness. The color can fade if left in direct sunlight for long periods.

Field identification & locations

Identify by its characteristic purple color and hexagonal prism crystal habits. Often found in basaltic rocks. Major locations include Brazil, Uruguay, Zambia, and South Korea.