mineral

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple variety: amethyst

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster; transparent to translucent purple and white crystals; hexagonal crystal structure with conchoidal fracture and no cleavage. The specimen appears to contain amethyst with white milky quartz, possibly with minor iron staining or matrix.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or volcanic cavities precipitate quartz; purple color results mainly from irradiation and iron impurities. Common amethyst deposits are geologically young to Precambrian, depending on locality, and the exact age cannot be determined visually.

Uses & applications

Used for jewelry, ornaments, polished specimens, and mineral collecting. Small rough clusters generally have modest commercial value.

Geological facts

Amethyst is the purple member of the quartz group and is the birthstone for February. Strong heating can turn some amethyst yellow or orange, producing citrine-like material.

Field identification & locations

Identify by purple quartz crystals, glassy luster, hardness that can scratch ordinary glass, and lack of cleavage; avoid confusing it with purple glass or fluorite, which is softer and cleaves readily. Major sources include Brazil, Uruguay, Zambia, Mexico, and the United States.