mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: Purple, green, clear, and white bands; Luster: Vitreous (glassy); Crystal structure: Isometric (cubic/octahedral); Cleavage: Perfect octahedral; Specific gravity: 3.18

Hardness: 4 on Mohs scale
Color: Purple, green, clear, and white bands
Luster: Vitreous (glassy)

Identified June 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in hydrothermal veins, often as a gangue mineral associated with metallic ores. It can also occur in sedimentary rocks like limestone or in igneous rocks like pegmatites. It forms across various geological ages when fluorine-rich fluids circulate through fractures.

Uses & applications

Used as a flux in steel and aluminum smelting, in the manufacturing of hydrofluoric acid, as high-clarity lenses for telescopes/microscopes, and extensively in jewelry and ornamental carvings.

Geological facts

Fluorite is famous for its wide range of colors and is the namesake for the phenomenon of 'fluorescence,' as many specimens glow under UV light. It is often called 'the most colorful mineral in the world.'

Field identification & locations

Identified in the field by its hardness (it can be scratched by a knife but not a copper penny) and its distinctive four directions of perfect cleavage. Commonly found in China, Mexico, and Illinois (USA). Collectors look for vibrant banding and well-formed cubic crystals.