mineral

Amethyst

Silicon Dioxide with iron impurities (SiO2)

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

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

Identified June 8, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in hydrothermal veins and cavities (geodes) of igneous rocks when silica-rich water cools. The purple color is caused by natural irradiation and iron impurities within the quartz crystal lattice.

Uses & applications

Primarily used in jewelry (rings, necklaces, beads) and as decorative display specimens. It is the birthstone for February and highly valued by mineral collectors.

Geological facts

Amethyst is the most valuable variety of quartz. Its name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was once believed to prevent drunkenness. Large geodes can be found in Brazil that are several feet tall.

Field identification & locations

Identify by its characteristic purple color, hardness (will scratch glass), and lack of cleavage. Common in Brazil, Uruguay, Zambia, and Arizona. In the field, look for hexagonal crystal shapes with pyramid-like terminations.