gemstone
Amethyst
Quartz (Silicon Dioxide, SiO2)
Hardness: 7 on the Mohs scale. Color ranges from light pinkish-purple to deep purple. Luster: Vitreous (glassy). Crystal system: Trigonal. Cleavage: None. Specific gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color ranges from light pinkish-purple to deep purple. Luster: Vitreous (glassy). Crystal system: Trigonal. Cleavage: None. Specific gravity: 2.65.
Formation & geological history
Forms in gas cavities (vesicles) in volcanic rocks, known as geodes or amygdules, where silica-rich hydrothermal fluids precipitate quartz crystals over millions of years.
Uses & applications
Primarily used as a gemstone in fine jewelry, rings, necklaces, and as decorative ornamental carvings or crystal specimens for collectors.
Geological facts
Amethyst was once considered one of the cardinal precious gemstones alongside diamond, ruby, sapphire, and emerald, until large deposits were found in Brazil in the 19th century.
Field identification & locations
Identified by its distinct purple color, vitreous luster, and lack of cleavage with conchoidal fracture. Found worldwide, with major deposits in Brazil, Uruguay, Zambia, and the USA.
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