mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2) with iron impurities
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/glassy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Purple, violet, or lavender
- Luster
- Vitreous/glassy
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Physical properties
Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/glassy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or geodes where silica-rich water cools. The purple color comes from irradiation of trivalent iron (Fe3+) in the quartz structure. Typically formed during the late stages of volcanic activity.
Uses & applications
Primarily used in jewelry (faceting, cabochons), as decorative display pieces (geodes), and for metaphysical or collection purposes.
Geological facts
Amethyst was considered a precious stone on par with diamonds until large deposits were discovered in Brazil in the 19th century. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identified by its purple color and ability to scratch glass. Tumbled stones like this one are common in shops. Found globally with significant deposits in Brazil, Uruguay, and Zambia.
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