mineral
Amethyst Quartz
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Pale purple to violet with clear zones; Luster: Vitreous (glassy); Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Pale purple to violet with clear zones
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Pale purple to violet with clear zones; Luster: Vitreous (glassy); Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or geodes when silica-rich water cools. The purple color is caused by natural irradiation or iron impurities within the quartz lattice. Found globally in igneous and metamorphic environments.
Uses & applications
Primarily used as a gemstone in jewelry, for decorative items, lapidary arts, and by mineral collectors. Large specimens are used in architectural decor.
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.
Field identification & locations
Identify by its 7 hardness (scratches glass), purple color, and lack of cleavage. Common in Brazil, Uruguay, and Africa. Small tumbled stones are basic entry points for new collectors.
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