gemstone
Amethyst
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Purple, violet, Lavender; Luster: Vitreous/Glassy; Crystal structure: Trigonal (hexagonal prisms); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, Lavender
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, Lavender; Luster: Vitreous/Glassy; Crystal structure: Trigonal (hexagonal prisms); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65
Formation & geological history
Found within geode cavities in volcanic rock or in hydrothermal veins, formed by minerals depositing into gas bubbles (amygdules) as lava cools. Common in basalt.
Uses & applications
Highly valued as a gemstone in jewelry (rings, necklaces, carvings), decorative decor (cathedral geodes), and collector specimens.
Geological facts
The name comes from the Greek 'amethystos', meaning 'not intoxicated', due to an ancient belief that it protected the wearer from drunkenness. The purple color is caused by trace amounts of iron and natural irradiation.
Field identification & locations
Identify by its unique purple hue and hexagonal crystal structure. Commonly found in Brazil, Uruguay, Zambia, and Canada. In the field, look for nodules or geodes within volcanic basalt formations.
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