mineral

Amethyst

Amethyst (SiO2 with Iron impurities)

Hardness: 7 on the Mohs scale; Color: Ranges from pale lilac to deep reddish-purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Ranges from pale lilac to deep reddish-purple
Luster: Vitreous (glassy)

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins or as linings within volcanic rock geodes. The purple color is caused by natural irradiation of trace iron impurities within the silicon dioxide structure. Formation can occur over millions of years as silica-rich water flows through rock cavities.

Uses & applications

Primarily used as a gemstone for jewelry (beads, faceted stones, cabochons), decorative home decor (geodes and cathedrals), and as a popular specimen for mineral collectors.

Geological facts

Amethyst was once considered one of the 'Cardinal Gems' alongside diamond, ruby, emerald, and sapphire until large deposits were found in Brazil. The name comes from the Greek 'amethystos', meaning 'not intoxicated', as it was historically believed to prevent drunkenness.

Field identification & locations

Identify in the field by its distinct purple color, hexagonal crystal shape, and inability to be scratched by a steel pocket knife. Found globally with major deposits in Brazil and Uruguay. Collectors should look for deep, uniform color and high transparency.