gemstone
Amethyst
Quartz (Silicon Dioxide, SiO2)
Hardness: 7 on Mohs scale; Color: Purple, violet, pale lilac; Luster: Vitreous (glassy); Crystal structure: Trigonal (hexagonal system); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, pale lilac
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, pale lilac; Luster: Vitreous (glassy); Crystal structure: Trigonal (hexagonal system); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Forms in hydrothermal veins and gas cavities (vugs/geodes) in volcanic rocks, where silica-rich solutions precipitate quartz crystals at low temperatures.
Uses & applications
Used widely in jewelry as a gemstone, ornamental carvings, crystal healing, and as mineral specimens for collectors.
Geological facts
The purple color of amethyst is caused by irradiation, iron impurities, and the presence of trace elements. In ancient times, it was valued as much as diamond.
Field identification & locations
Can be identified by its distinct purple color and 7 Mohs hardness which scratches glass. Found commonly in Brazil, Uruguay, Zambia, and parts of the USA.
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