mineral

Amethyst cluster

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

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster; translucent purple crystals with hexagonal prismatic structure and conchoidal fracture; no prominent cleavage; specific gravity about 2.65.

Identified August 23, 2026More mineral →

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Physical properties

Hardness 7 Mohs; vitreous luster; translucent purple crystals with hexagonal prismatic structure and conchoidal fracture; no prominent cleavage; specific gravity about 2.65.

Formation & geological history

Forms in gas cavities and fractures of volcanic rocks, especially basalt, when silica-rich hydrothermal fluids deposit quartz. Most specimens formed during relatively young volcanic and hydrothermal events, commonly in the Cenozoic to Mesozoic eras.

Uses & applications

Used as a gemstone, ornamental cluster, lapidary material, and collector specimen; large crystal clusters are displayed rather than used structurally.

Geological facts

Color ranges from pale lilac to deep violet; heating can produce yellow citrine. Amethyst is the February birthstone and a variety of quartz, not a separate mineral species.

Field identification & locations

Identify by purple color, glassy luster, quartz hardness, and six-sided crystal faces; common sources include Brazil, Uruguay, Zambia, and Namibia. Value depends on saturation, crystal form, size, and damage.