mineral
Amethyst Geode
Amethyst (Silicon Dioxide, SiO2 with iron impurities)
Hardness: 7 on Mohs scale; Color: Purple, violet, or pale lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, or pale lavender
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, or pale lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed inside volcanic basalt rocks or sedimentary cavities where gas bubbles or hollow pockets were filled over millions of years by silica-rich hydrothermal fluids. The purple color is caused by gamma irradiation of trace iron within the quartz lattice.
Uses & applications
Primarily used for decorative display, energy healing/meditation practices, lapidary art, and jewelry setting when cut into faceted stones or cabochons.
Geological facts
Until the discovery of large deposits in Brazil in the 1700s, amethyst was considered a 'Cardinal Gem' and was as valuable as diamond, ruby, and sapphire.
Field identification & locations
Identify in the field by looking for rounded, potato-like nodules (vugs) that feel unexpectedly light for their size. In the field, look for quartz outcroppings or basalts in locations like Brazil, Uruguay, or Arizona.
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