gemstone
Amethyst
Silicon Dioxide (SiO2) with iron impurities
AI-generated identification · may be incorrectHardness: 7 on Mohs scale. Color: pale violet to purple. Luster: vitreous (glassy). Crystal structure: trigonal/hexagonal. Cleavage: none, conchoidal fracture. Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- pale violet to purple
- Luster
- vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale. Color: pale violet to purple. Luster: vitreous (glassy). Crystal structure: trigonal/hexagonal. Cleavage: none, conchoidal fracture. Specific gravity: 2.65.
Formation & geological history
Forms inside volcanic cavities (geodes) or hydrothermal veins when silicon dioxide crystallizes from iron-rich hydrothermal fluids at low to moderate temperatures.
Uses & applications
Widely used in jewelry, lapidary art, gemstone collecting, and ornamental carvings.
Geological facts
The purple color comes from trace amounts of iron irradiation in the crystal structure. Ancient Greeks believed amethyst could prevent drunkenness, deriving its name from 'amethystos' meaning 'not intoxicated'.
Field identification & locations
Identified by its purple coloration, hardness of 7 (scratches glass, cannot be scratched by steel), glassy luster, and conchoidal fracture. Commonly found in Brazil, Uruguay, Madagascar, Zambia, and Russia.
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