mineral

Mixed quartz specimens, including amethyst

Quartz (SiO₂), with purple amethyst variety; possible milky or included quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; typically vitreous luster, conchoidal fracture, and hexagonal crystal structure. The purple piece is likely amethyst, while the colorless-to-white pieces appear to be milky or clear quartz; exact identification is limited by the image.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, cavities in volcanic rocks, and pegmatites. Amethyst commonly forms in geodes and volcanic vesicles, generally from relatively young to Precambrian deposits.

Uses & applications

Used for gemstones, ornaments, crystal collecting, abrasives, glassmaking, electronics, and industrial silica. Amethyst has jewelry and decorative value.

Geological facts

Purple color in amethyst is mainly caused by iron impurities and natural irradiation. Quartz is one of Earth’s most abundant minerals and commonly forms six-sided prisms with pyramidal ends.

Field identification & locations

Identify quartz by its glassy luster, lack of cleavage, conchoidal fracture, and ability to scratch ordinary glass; amethyst is distinguished by purple coloration. Common sources include Brazil, Uruguay, Zambia, Madagascar, and the United States.