Rock Identifier
Amethyst (Faceted) (Silicon Dioxide with Iron impurities (SiO2)) — mineral
mineral

Amethyst (Faceted)

Silicon Dioxide with Iron impurities (SiO2)

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/Glassy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness
7 on Mohs scale
Color
Purple, violet, or lavender
Luster
Vitreous/Glassy
Identified More mineral

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Physical properties

Hardness: 7 on Mohs scale; Color: Purple, violet, or lavender; Luster: Vitreous/Glassy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins or geodes when silica-rich water deposits quartz crystals. The purple color is caused by irradiation of trivalent iron (Fe3+) impurities. They are found in volcanic rocks (basalts) and cavities of metamorphic rocks.

Uses & applications

Primary use is in jewelry (faceted gemstones, cabochons, beads). Also popular as collector specimens and in alternative healing/spirituality.

Geological facts

Amethyst was considered one of the 'Cardinal gems' until large deposits were found in Brazil. The name comes from the Ancient Greek 'amethystos', meaning 'not intoxicated', as it was believed to prevent drunkenness.

Field identification & locations

Identify by its distinctive purple hue and hexagonal crystal habit in the rough. In faceted form, look for color zoning and vitreous luster. Commonly found in Brazil, Uruguay, Zambia, and South Korea.