mineral

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous/Glassy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Pale lilac to deep purple
Luster: Vitreous/Glassy

Identified May 16, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous/Glassy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and hollow cavities (geodes). The purple color comes from irradiation of trivalent iron (Fe3+) in the quartz structure. These can form in volcanic or sedimentary environments.

Uses & applications

Primarily used for high-quality jewelry, lapidary arts, and as a popular specimen for mineral collectors and decorative items.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones alongside diamond, sapphire, ruby, and emerald. Ancient Greeks believed it prevented intoxication.

Field identification & locations

Identify by its distinct purple hue and quartz-like hexagonal crystal habit or conchoidal fracture. Found worldwide, with major deposits in Brazil and Uruguay. Collectors should look for deep, uniform color and clarity.