mineral

Amethyst Quartz

Amethyst (Silicon Dioxide, SiO2)

Hardness: 7 on the Mohs scale; Color: Purple, violet; Luster: Vitreous (glassy); Crystal structure: Trigonal (Hexagonal system); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

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

Identified May 24, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Purple, violet; Luster: Vitreous (glassy); Crystal structure: Trigonal (Hexagonal system); Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins or as linings in volcanic geodes (vugs) when silica-rich fluids cool and crystallize in the presence of iron impurities and irradiation.

Uses & applications

Primarily used in jewelry (faceting and cabochons), as decorative display specimens, and in metaphysical rock collecting.

Geological facts

The purple color is caused by trace amounts of iron and aluminum combined with natural radiation from surrounding rocks. Historically, Greeks believed it could prevent intoxication.

Field identification & locations

Identify by its hexagonal crystal habit (if points are present), purple color, and ability to scratch glass but not topaz. Commonly found in Brazil, Uruguay, and Namibia.