mineral

Tumbled blue fluorite (likely)

Fluorite, calcium fluoride (CaF₂)

AI-generated identification · may be incorrect

Small polished stone with deep blue-violet color, vitreous luster, and translucent zones or internal fractures. Hardness is Mohs 4, cubic crystal structure, perfect octahedral cleavage, and specific gravity about 3.18; the blue color may be natural or enhanced.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Fluorite forms mainly in hydrothermal veins and replacement deposits, crystallizing from mineral-rich fluids in cavities and fractures, commonly during the Paleozoic–Mesozoic eras. Major sources include China, Mongolia, England, Mexico, and the United States.

Uses & applications

Used as a decorative, lapidary, and collector stone; industrial fluorite is an important source of fluorine and flux in steelmaking and glass production. Tumbled pieces commonly sell for about $3–$15.

Geological facts

Its cubic crystals and unusually perfect cleavage are diagnostic, although polishing obscures crystal form. Blue fluorite can fade with prolonged sunlight or heat.

Field identification & locations

Identify it by its cool glassy luster, zoning, relatively low hardness, and possible cubic cleavage; it should scratch with a steel knife but not ordinary glass reliably. Exact identification would require testing, since blue apatite, glass, and dyed quartz can look similar.