mineral
Amethyst (Rough Crystal)
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 Mohs; Color: Light to deep purple/violet; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None; SG: 2.65
- Hardness
- 7 Mohs
- Color
- Light to deep purple/violet
- Luster
- Vitreous
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Physical properties
Hardness: 7 Mohs; Color: Light to deep purple/violet; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None; SG: 2.65
Formation & geological history
Forms in hydrothermal veins or volcanic geodes when silicon dioxide and trace amounts of iron are irradiated by natural gamma radiation from surrounding rocks. Commonly found in basaltic rocks.
Uses & applications
Primarily used in jewelry, as decorative display specimens, and in alternative healing practices (crystal healing). Larger specimens are used in industrial lapidary.
Geological facts
Amethyst was considered as valuable as diamonds until large deposits were found in Brazil in the 1700s. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify by its characteristic purple hue and hexagonal crystal habit. Common locations include Brazil, Uruguay, Zambia, and Ontario. Collectors look for clarity and deep saturation.
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