mineral
Amethyst
Silicon dioxide (Quartz variety), SiO2
Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glassy); Crystal structure: Trigonal (hexagonal crystal system); Cleavage: None (exhibits conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple to violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glassy); Crystal structure: Trigonal (hexagonal crystal system); Cleavage: None (exhibits conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Forms in hydrothermal veins and vugs, particularly within basaltic volcanic rocks, where silica-rich solutions cool and crystallize over millions of years.
Uses & applications
Widely used in gemstone jewelry, ornamental carvings, spiritual and holistic practices, and crystal collection.
Geological facts
Amethyst was once considered one of the cardinal gemstones of high value until extensive deposits were discovered in Brazil. Its purple color is caused by irradiation and trace amounts of iron substituting for silicon within the quartz lattice.
Field identification & locations
Identified by its distinct purple color, hexagonal crystal form, and conchoidal fracture. Commonly found in Brazil, Uruguay, Zambia, and the USA. This particular specimen has been cut and polished into a double-terminated quartz crystal shape.
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