mineral

Amethyst

Silicon dioxide (SiO2)

Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified July 29, 2026More mineral →

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Physical properties

Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Forms in hydrothermal veins, volcanic gas cavities, or as linings of geodes, typically through the irradiation of trace iron impurities within a quartz crystal lattice.

Uses & applications

Widely used in jewelry, ornamental carvings, metaphysical practices, and mineral collections.

Geological facts

The purple color is caused by irradiation, iron impurities, and the presence of other trace elements. Historically, amethyst was considered a precious gemstone equivalent in value to diamonds, rubies, and emeralds until large deposits were discovered in Brazil.

Field identification & locations

Identified by its distinctive purple color, hexagonal crystal structure with pyramidal terminations (often doubly terminated in specimens like this), and lack of cleavage. Commonly found in Brazil, Uruguay, Zambia, and the United States.