mineral
Amethyst
Silicon Dioxide (Quartz variety), SiO2
Hardness: 7 on Mohs scale; Color: Purple, violet, to 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, to pale lilac
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, to pale lilac; Luster: Vitreous (glassy); Crystal structure: Trigonal (hexagonal system); Cleavage: None, exhibits conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Formed within gas cavities (vugs or geodes) in volcanic rocks through the deposition of silica-rich hydrothermal fluids containing trace amounts of iron, which are irradiated over millions of years.
Uses & applications
Widely used in jewelry, as a collector's specimen, in lapidary arts, and historically as a talisman or decorative gemstone.
Geological facts
Amethyst was once considered one of the cardinal gemstones of high value until large deposits were discovered in Brazil. Its purple color comes from iron impurities combined with natural irradiation.
Field identification & locations
Easily identified by its distinct purple coloration and hexagonal crystal points growing from a matrix. Commonly found in Brazil, Uruguay, Zambia, and the USA.
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