mineral
Amethyst
Silicon Dioxide (SiO2 with iron impurities)
Hardness: 7 on Mohs scale. Color: Violet to deep purple. Luster: Vitreous/glassy. Crystal structure: Hexagonal/trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Violet to deep purple
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7 on Mohs scale. Color: Violet to deep purple. Luster: Vitreous/glassy. Crystal structure: Hexagonal/trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
Formation & geological history
Forms primarily within hydrothermal veins and gas cavities (geodes) of volcanic igneous rocks, where silica-rich solutions deposit quartz over time under influence of natural irradiation.
Uses & applications
Widely used in jewelry making, ornamental carvings, lapidary art, and popular among mineral collectors.
Geological facts
Amethyst's distinct purple color comes from trace amounts of iron (Fe3+) irradiated by natural gamma radiation in surrounding rocks. In ancient Greece, it was believed to prevent intoxication.
Field identification & locations
Identified by its characteristic purple color, hardness of 7 (scratches glass), and glassy luster with conchoidal fracturing. Major sources include Brazil, Uruguay, Madagascar, and Zambia.
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