mineral

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Purple, violet, or lavender
Luster: Vitreous (glassy)

Identified March 29, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins and geodes within igneous, sedimentary, and metamorphic environments. The purple color comes from irradiation of trivalent iron impurities (Fe3+) in the quartz structure. These occurrences can date back millions of years depending on the host rock cavity formation.

Uses & applications

Primarily used as a gemstone for jewelry, ornamental carvings, and as a popular mineral for collectors and home décor due to its aesthetic appeal and durability.

Geological facts

Until the 18th century, amethyst was included in the cardinal (most valuable) gemstones alongside diamond, sapphire, ruby, and emerald. Ancient Greeks believed it could prevent intoxication. Large geodes are commonly found in Brazil and Uruguay.

Field identification & locations

Identify in the field by its distinct purple hue and six-sided prismatic crystal shape terminating in a point. It lacks cleavage and will scratch glass. Common locations include Brazil, Uruguay, Madagascar, and Arizona, USA.