mineral

Amethyst

Amethyst (Silicon Dioxide, SiO2 with iron impurities)

Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Pale lilac to deep purple
Luster: Vitreous (glassy)

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Pale lilac to deep purple; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None; Specific Gravity: 2.65

Formation & geological history

Forms inside gas cavities (geodes) in volcanic rocks or in hydrothermal veins when silica-rich water cools. Most commercial deposits are from the Mesozoic or Cenozoic eras.

Uses & applications

Widely used for jewelry (faceted stones), decorative home decor (geode cathedrals), and as a popular specimen for mineral collectors.

Geological facts

The purple color comes from irradiation of trivalent iron impurities in the quartz structure. Ancient Greeks believed it could prevent intoxication.

Field identification & locations

Identify by its characteristic purple color and hexagonal prism crystal habits. Commonly found in Brazil, Uruguay, and Zambia. In the field, look for hollow volcanic basalt rocks.

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