mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: Purple, green, blue, or colorless; Luster: Vitreous (glassy); Crystal structure: Isometric (often forming cubes or octahedrons); Cleavage: Perfect octahedral; Specific Gravity: 3.1-3.3

Hardness: 4 on Mohs scale
Color: Purple, green, blue, or colorless
Luster: Vitreous (glassy)

Identified June 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in hydrothermal veins, often as a gangue mineral associated with metallic ores. It can also be found in vugs within limestones and dolomites. Formations occur across various geological ages from the Proterozoic to the Cenozoic.

Uses & applications

Used as a flux in steel and aluminum smelting, in the production of hydrofluoric acid, as high-clarity lenses for telescopes and cameras, and as a popular semi-precious gemstone for jewelry and décor.

Geological facts

Fluorite is famous for its wide variety of brilliant colors and its property of fluorescence under UV light, from which the term 'fluorescence' was actually derived. Some specimens can show distinct color zoning within a single crystal.

Field identification & locations

Identified in the field by its distinct cubic or octahedral shape, perfect cleavage, and relative softness (can be scratched by a knife but not a copper penny). Common locations include Illinois and Kentucky (USA), China, Mexico, and South Africa.