mineral
Amethyst
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale; purple color ranging from pale lilac to deep violet; vitreous (glass-like) luster; trigonal crystal system; conchoidal fracture with no true cleavage; specific gravity of 2.65
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Physical properties
Hardness of 7 on the Mohs scale; purple color ranging from pale lilac to deep violet; vitreous (glass-like) luster; trigonal crystal system; conchoidal fracture with no true cleavage; specific gravity of 2.65
Formation & geological history
Forms within gas cavities (vesicles) in basaltic volcanic rocks, or as linings in hydrothermal veins, where silica-rich solutions precipitate quartz crystals over millions of years.
Uses & applications
Widely used as a gemstone in jewelry, for decorative items, spiritual and metaphysical practices, and as collector specimens.
Geological facts
The purple color in amethyst is caused by irradiation, iron impurities, and the presence of trace elements. Ancient Greeks and Romans believed amethyst could prevent intoxication, which is where its name (derived from the Greek 'amethustos', meaning 'not intoxicated') originates.
Field identification & locations
Easily identified by its distinctive purple color and hexagonal crystal termination. Found globally, with notable deposits in Brazil, Uruguay, Zambia, and the United States.
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