mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: typically purple, green, or blue as seen here; Luster: Vitreous (glassy); Crystal structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific gravity: 3.17 to 3.56.

Hardness: 4 on Mohs scale
Color: typically purple, green, or blue as seen here
Luster: Vitreous (glassy)

Identified June 27, 2026More mineral →

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Physical properties

Formation & geological history

Fluorite typically forms in hydrothermal veins, often occurring alongside lead and silver ores. It can also be found in vugs within limestone or as a late-stage crystallization in igneous rocks like granite.

Uses & applications

Extensively used in metallurgy as a flux and in the production of hydrofluoric acid. In jewelry, it is used for ornamental carvings, though its low hardness limits use in rings. High-purity fluorite is used for specialized optical lenses.

Geological facts

Fluorite is famous for its fluorescence under UV light, a property that actually took its name from the mineral. Significant deposits include the famous 'Blue John' cavern in Derbyshire, England.

Field identification & locations

Identify in the field by its distinct translucent colors, glass-like luster, and its ability to be scratched by a steel knife but not a copper penny. Look for cubic shapes or octahedral cleavage fragments in mining districts.