mineral
Amethyst
Quartz (Silicon Dioxide, SiO2)
Hardness: 7 on the Mohs scale. Color: Purple, violet, to dark purple. Luster: Vitreous (glassy). Crystal structure: Trigonal (hexagonal system). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Color
- Purple, violet, to dark purple
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color: Purple, violet, to dark purple. Luster: Vitreous (glassy). Crystal structure: Trigonal (hexagonal system). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.
Formation & geological history
Formed in gas cavities (vesicles) of volcanic rocks through the precipitation of silica-rich hydrothermal fluids containing trace amounts of iron.
Uses & applications
Widely used in jewelry, decorative items, crystal healing, and as collector specimens.
Geological facts
Amethyst was once considered one of the cardinal gemstones of high value until large deposits were discovered in Brazil. Its purple color is caused by irradiation and trace iron impurities.
Field identification & locations
Identified by its distinct purple color, hexagonal crystal prism shape, and hardness of 7 which scratches glass. Found worldwide, with major deposits in Brazil, Uruguay, Zambia, and the USA.
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