mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs scale), Color: light to deep purple (due to irradiation and iron), Luster: Vitreous, Crystal structure: Trigonal (Hexagonal prisms), Cleavage: None/Conchoidal fracture, Specific gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: light to deep purple (due to irradiation and iron), Luster: Vitreous, Crystal structure: Trigonal (Hexagonal prisms), Cleavage: None/Conchoidal fracture, Specific gravity: 2.65
Formation & geological history
Forms in geodes or hydrothermal veins within igneous and metamorphic rocks. Most large-scale deposits are associated with volcanic basalt flows or pegmatites.
Uses & applications
Primarily used as a gemstone in jewelry (faceting, cabochons), for decorative carvings, and highly popular as display specimens for collectors.
Geological facts
Amethyst was considered a precious stone comparable to diamond until massive deposits were discovered in Brazil in the 18th century. Its name comes from the Greek 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identified by its purple hue and hexagonal crystal habitat. Common in Brazil, Uruguay, and Africa. Look for prismatic crystals with pyramid-shaped terminations often found in cavities of volcanic rock.
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