mineral
Amethyst
Silicon dioxide (SiO2) with iron impurities
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, to deep reddish-purple
- Luster
- Vitreous
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, to deep reddish-purple; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins and gas cavities (geodes) within volcanic rocks. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities. They are found in rocks of various geological ages, often Cretaceous to present.
Uses & applications
Primarily used as a gemstone in jewelry (rings, bracelets, necklaces), as decorative specimens for mineral collectors, and in alternative medicine/metaphysics.
Geological facts
Amethyst was considered a 'Precious Stone' until large deposits were found in Brazil. The name comes from the Greek 'amethystos', meaning 'not intoxicated', as it was once believed to prevent drunkenness.
Field identification & locations
Identify by its characteristic purple color and ability to scratch glass (hardness 7). In the field, look for purple crystals inside hollow amygdaloidal basalt or geodes. Major deposits are found in Brazil, Uruguay, Zambia, and Ontario.
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Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous