mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: typically green, purple, clear, or yellow; Luster: Vitreous; Crystal Structure: Isometric (cubic/octahedral); Cleavage: Perfect octahedral in four directions; Specific Gravity: 3.18

Hardness: 4 on Mohs scale
Color: typically green, purple, clear, or yellow
Luster: Vitreous

Identified May 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal activity, often as a vein mineral in metallic deposits or in sedimentary environments like limestone after interaction with fluorine-rich fluids. Found in a wide range of geological ages.

Uses & applications

Primary source of fluorine for hydrofluoric acid; used as a flux in steel making, in ceramic glazes, and for high-performance optical lenses. Collected as a semi-precious gemstone and mineral specimen.

Geological facts

Fluorite was the first mineral from which the phenomenon of fluorescence was studied and named. It is known as the 'most colorful mineral in the world' due to the huge variety of hues caused by impurities.

Field identification & locations

Identify by its '4' hardness (scratchable by a knife but not a penny) and its characteristic four-way cleavage. Commonly found in Illinois (USA), China, Mexico, and England. Collectors should look for sharp cubic crystals.