mineral

Rainbow fluorite

Fluorite (calcium fluoride, CaF₂)

AI-generated identification · may be incorrect

A polished, banded specimen showing pale purple and green zoning; vitreous luster and cubic crystal structure, though the cut surface hides crystal form. Mohs hardness 4, perfect octahedral cleavage, and specific gravity about 3.18.

Identified September 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in hydrothermal veins and replacement deposits when fluorine-rich fluids precipitate calcium fluoride, commonly alongside quartz, calcite, and galena. The specimen’s exact geological age cannot be determined from the image; fluorite deposits range from Precambrian to recent geological periods.

Uses & applications

Used industrially as a flux in steel and aluminum production and as a source of hydrofluoric acid; transparent colorful material is cut for cabochons, carvings, and display specimens.

Geological facts

Purple coloration commonly reflects radiation-related color centers or trace impurities, while green bands arise from differing trace-element chemistry. Fluorite is the official Mohs hardness-4 reference mineral.

Field identification & locations

Identify by its unusually low hardness, strong cleavage, cubic habit, and purple-green color zoning; a steel knife can scratch it. Important localities include China, Mexico, England, Illinois, and parts of Spain.