mineral

Raw amethyst

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to violet, with vitreous luster and conchoidal fracture. It has hexagonal quartz crystal structure, typically without prominent cleavage; purple color comes from iron-related defects and irradiation.

Identified September 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in gas cavities of volcanic basalt when silica-rich groundwater deposits quartz and amethyst layers. Most specimens are Cenozoic to Mesozoic, though age varies by locality.

Uses & applications

Used for cabochons, carvings, beads, display specimens, and occasional faceted gemstones; lower-grade material is common in decorative objects.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Heating can turn it yellow-orange, producing citrine or ametrine-like material.

Field identification & locations

Identify by purple zoning, glassy luster, hardness sufficient to scratch ordinary glass, and lack of obvious cleavage; distinguish it from fluorite, which is softer and cleaves readily. Common sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.