mineral

Amethyst (Druzy Quartz)

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Hardness: 7 on Mohs scale; Color: light to deep purple; Luster: vitreous (glassy); Crystal Structure: hexagonal/trigonal; Cleavage: none (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: light to deep purple
Luster: vitreous (glassy)

Identified April 7, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: light to deep purple; Luster: vitreous (glassy); Crystal Structure: hexagonal/trigonal; Cleavage: none (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or cavities (geodes) within volcanic rocks through a process of silica precipitation from groundwater over thousands to millions of years. The purple color is caused by irradiation and the presence of trace iron impurities.

Uses & applications

Predominantly used in jewelry, as gemstone specimens for collectors, and in decorative items/metaphysical practices.

Geological facts

Until the 18th century, amethyst was included in the cardinal gemstones along with diamond, ruby, sapphire, and emerald. Large deposits in Brazil significantly lowered its market value.

Field identification & locations

Identify in the field by looking for purple hexagonal crystal points inside hollow or semi-hollow basalt or agate nodules. Commonly found in Brazil, Uruguay, South Korea, and the United States (AZ, GA).

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