mineral

Amethyst quartz crystal cluster

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; purple to violet color, vitreous luster, hexagonal crystal structure, no cleavage, conchoidal fracture, specific gravity about 2.65. The specimen appears to be a natural druzy crystal cluster on a pale matrix or cut base.

Identified August 31, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst commonly crystallizes in cavities of volcanic basalt from silica-rich hydrothermal fluids; many commercial deposits formed during the Mesozoic, especially in Brazil and Uruguay. Its exact age and locality cannot be determined from the image.

Uses & applications

Used for cabinet specimens, ornamental carvings, beads, and jewelry; larger clusters are popular decorative pieces. Common examples typically sell for about $20–$150, while large, intensely colored, well-formed clusters can exceed $500.

Geological facts

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

Field identification & locations

Identify it by purple transparent-to-translucent quartz crystals with glassy luster and pointed hexagonal terminations; it should scratch glass but not corundum. Major sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.