mineral

Amethyst

Silicon Dioxide (SiO2) containing iron impurities

Hardness: 7 (Mohs scale); Color: Light to dark purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Light to dark purple
Luster: Vitreous (glassy)

Identified March 23, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Light to dark purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and cavities (geodes) of igneous and metamorphic rocks. The purple color results from gamma irradiation and the presence of trace iron (Fe3+) in the quartz crystal lattice.

Uses & applications

Primarily used as a gemstone for jewelry, carvings, and as decorative crystal specimens for collectors and metaphysical practices.

Geological facts

Until the 18th century discovery of large deposits in Brazil, amethyst was considered one of the 'Cardinal' precious gemstones, often valued as high as diamonds and rubies.

Field identification & locations

Identify by its characteristic purple color and ability to scratch glass. Commonly found in Brazil, Uruguay, and Zambia. Collectors should look for saturated color and clarity.

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