mineral

Amethyst druzy cluster

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Quartz has Mohs hardness 7, vitreous luster, hexagonal crystal structure, no cleavage, and specific gravity about 2.65. This specimen shows a pale-purple crystalline druzy coating on a rough matrix, likely with iron-related color zoning.

Identified August 27, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or groundwater deposit quartz in cavities and fractures, with trace iron later irradiated to produce purple amethyst. Most specimens formed in volcanic cavities during the Cenozoic or earlier, depending on locality.

Uses & applications

Used as a decorative specimen, jewelry stone, and lapidary material; large crystal clusters are popular display pieces. Amethyst is also a traditional February birthstone.

Geological facts

Darker purple generally increases gem value, though saturated color with good transparency is prized most. Heating commonly turns amethyst yellow-orange, producing citrine.

Field identification & locations

Identify by purple color, glassy quartz crystals, hardness sufficient to scratch glass, and lack of cleavage; beware dyed quartz and purple glass. Common sources include Brazil, Uruguay, Zambia, and Mexico.