mineral

Amethyst

Silicon Dioxide with iron impurities (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 July 9, 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 or geodes when silica-rich solutions consolidate in cavities within igneous rocks (primarily basalt). Geologic age varies based on the host rock, often Mesozoic or Cenozoic.

Uses & applications

Primarily used in jewelry, as birthstone for February, and as a popular semi-precious gemstone for mineral collectors and decorative items.

Geological facts

The purple color is caused by irradiation of trivalent iron (Fe3+) in the quartz structure. It was historically considered as valuable as diamonds, rubies, and emeralds until large deposits were found in Brazil.

Field identification & locations

Identify by its characteristic purple color, hardness (will scratch glass), and lack of cleavage. Look for it in volcanic regions, particularly within geode cavities. Common locations include Brazil, Uruguay, Zambia, and Canada.