mineral
Amethyst Geode
Silicon Dioxide with impurities (SiO2)
AI-generated identification · may be incorrectHardness: 7; Color: Purple to deep violet; Luster: Vitreous/glassy; Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65
- Hardness
- 7
- Color
- Purple to deep violet
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7; Color: Purple to deep violet; Luster: Vitreous/glassy; Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65
Formation & geological history
Formed in volcanic rock cavities (geodes) when silica-rich hydrothermal fluids precipitate over long periods. Usually found in basaltic rocks from the Mesozoic era.
Uses & applications
Used primarily in jewelry, as ornamental display specimens, in lapidary arts, and for gemstone collecting.
Geological facts
The purple color comes from irradiation of iron impurities within the quartz structure. It was once considered a Cardinal Gem along with diamond, ruby, emerald, and sapphire.
Field identification & locations
Identify by the crystal habit (six-sided prisms) and distinct purple hue. Commonly found in Brazil and Uruguay. Collectors look for deep saturation and lack of visible inclusions.
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