mineral

Amethyst and Gravel Collection

Amethyst (Silicon Dioxide, SiO2)

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous (glass-like), Crystal structure: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Identified June 2, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous (glass-like), Crystal structure: Trigonal/Hexagonal, Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or geodes when silica-rich fluids deposit quartz crystals. The purple color is caused by irradiation of iron impurities in the crystal lattice. These specimens are likely of recent geologic harvest from locations like Brazil or Uruguay.

Uses & applications

Used primarily in jewelry, as gemstone specimens for collectors, and in decorative arts. Smaller gravel specimens are used as aquarium substrate or for tumbling.

Geological facts

Amethyst is the birthstone for February. It was once considered a 'Cardinal Gem' and was as valuable as diamonds until large deposits were found in South America in the 19th century.

Field identification & locations

Identify by its purple color and hexagonal prism crystal habits. Often found in volcanic cavities. In the field, look for quartz-heavy outcrops or geodes.

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