gemstone
Amethyst
Quartz (SiO2)
Hardness: 7 on the Mohs scale. Color: Purple, violet, to pale reddish-violet. Luster: Vitreous (glassy). Crystal structure: Trigonal. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Color
- Purple, violet, to pale reddish-violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color: Purple, violet, to pale reddish-violet. Luster: Vitreous (glassy). Crystal structure: Trigonal. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.
Formation & geological history
Formed in gas cavities (vesicles) in volcanic rocks, or as linings in hydrothermal veins, where silica-rich solutions precipitate quartz crystals over millions of years.
Uses & applications
Widely used in jewelry, ornamental carvings, crystal healing, and as a popular mineral specimen for collectors.
Geological facts
The purple color is caused by irradiation, iron impurities, and the presence of trace elements. Ancient Greeks and Romans believed amethyst could prevent intoxication.
Field identification & locations
Identified by its distinctive purple color and vitreous luster; common worldwide with major deposits in Brazil, Uruguay, and Zambia.
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