mineral
Amethyst
Silicon dioxide (SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Purple, violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins and hollow cavities (geodes) within igneous rocks. The purple color is caused by trace amounts of iron and natural irradiation within the earth.
Uses & applications
Popular in jewelry, holistic practices, and as a collector's mineral specimen. Most prized when it has deep purple coloring.
Geological facts
Formerly considered one of the 'Cardinal Gems' alongside diamond, ruby, sapphire, and emerald until large deposits were found in Brazil in the 1800s. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identified by its purple color and hexagonal crystal terminations. Commonly found in Brazil, Uruguay, and Madagascar. Collectors look for deep shade saturation and lack of visible inclusions.
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