gemstone
Amethyst
Quartz (SiO2)
Hardness: 7 on the Mohs scale. Color: Light to dark purple or violet. Luster: Vitreous (glassy). Crystal Structure: Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on the Mohs scale
- Color
- Light to dark purple or violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on the Mohs scale. Color: Light to dark purple or violet. Luster: Vitreous (glassy). Crystal Structure: Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
Formation & geological history
Forms in hydrothermal veins, volcanic rocks (gas cavities in basalt), and metamorphic environments where silicon dioxide-rich solutions cool and crystallize over millions of years.
Uses & applications
Widely used in jewelry, decorative ornaments, crystal healing, and lapidary arts.
Geological facts
The purple color is caused by irradiation, iron impurities, and the presence of trace elements. Historically, it was considered a precious gemstone of equal value to diamond and ruby until large deposits were discovered in Brazil.
Field identification & locations
Easily identified by its distinctive purple color and conchoidal fracture. Common locations include Brazil, Uruguay, Madagascar, Zambia, and the United States.
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