mineral

Amethyst Geode

Amethyst (SiO2 with iron impurities)

Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple to violet; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in gas cavities (vesicles) within volcanic rocks or hydrothermal veins. Silica-rich water crystallizes over time; the purple color is caused by irradiation and trace iron impurities.

Uses & applications

Used extensively in jewelry (gemstones), ornamental decor, and mineral collections. Highly valued by practitioners of metaphysical crystal healing and as a birthstone (February).

Geological facts

The largest amethyst geodes are found in the Artigas region of Uruguay. Historically, ancient Greeks believed amethyst could prevent intoxication. It is the most prized variety of quartz.

Field identification & locations

Identified by its characteristic purple crystals growing inward toward the center of a cavity. Commonly found in Brazil, Uruguay, and Madagascar. Look for a dull, rock-like exterior with a hollow, crystalline interior.