mineral

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Hardness: 7 (Mohs scale); Color: Purple/Violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (pyramidal terminations); Cleavage: None; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Purple/Violet
Luster: Vitreous (glassy)

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Purple/Violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (pyramidal terminations); Cleavage: None; Specific Gravity: 2.65

Formation & geological history

Formed in hollow cavities (vugs) of basaltic or volcanic rock. Hydrothermal precipitates deposited minerals as groundwater rich in silica entered these cavities over millions of years, often during the Cenozoic era.

Uses & applications

Used extensively in jewelry (faceted gemstones, beads), home decor as ornamental geodes, and valued by mineral collectors for its aesthetic quality.

Geological facts

Amethyst derives its name from the Greek word 'amethystos', meaning 'not intoxicated', based on the ancient belief that the stone protected its owner from drunkenness. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities in the quartz lattice.

Field identification & locations

Identify by its distinctive purple color and hexagonal prism crystals terminating in points. Commonly found in Brazil, Uruguay, and Madagascar. In the field, look for round volcanic nodules with white or gray rinds that, when cracked open, reveal crystalline interiors.

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