mineral
Amethyst
Quartz (SiO2)
Hardness: 7 on the Mohs scale. Color: Purple, violet, dark pinkish-purple. Luster: Vitreous (glassy). Crystal structure: Trigonal (hexagonal system). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Color
- Purple, violet, dark pinkish-purple
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color: Purple, violet, dark pinkish-purple. Luster: Vitreous (glassy). Crystal structure: Trigonal (hexagonal system). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.
Formation & geological history
Formed within gas cavities (vesicles) in basaltic volcanic rocks, or as linings in hydrothermal veins, where silica-rich solutions deposit quartz crystals over time.
Uses & applications
Widely used as a gemstone in jewelry, for decorative items, crystal healing, and mineral specimen collecting.
Geological facts
Amethyst was once as valuable as diamond, ruby, and emerald until large deposits were discovered in Brazil during the 19th century. Its purple color is caused by irradiation and trace amounts of iron substituting for silicon in the crystal lattice.
Field identification & locations
Easily identified by its distinct purple color and hexagonal crystal termination. Common locations include Brazil, Uruguay, Zambia, and the USA (Arizona).
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