Mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness 4 on the Mohs scale, vitreous luster, isometric crystal system, perfect cleavage in four directions forming octahedrons. Found in a wide variety of colors including purple, green, yellow, blue, and colorless. Often shows color zoning.

Identified June 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins, often associated with metallic ores. Can also occur as a deposit from hot springs, in sedimentary rocks like limestone, and in granite pegmatites.

Uses & applications

Used historically as a flux in steelmaking. A major source of fluorine and hydrofluoric acid for chemical industries. Used in specialized optics. Widely collected as a mineral specimen and carved into ornamental objects. Too soft for mainstream jewelry but used in beads and cabochons.

Geological facts

The phenomenon of fluorescence was named after fluorite, as many specimens strongly fluoresce under ultraviolet light. Often referred to as the 'most colorful mineral in the world'.

Field identification & locations

Identified by its octahedral cleavage, cubic crystal habit, hardness of 4 (can be scratched by a knife but not a copper penny), and specific gravity. Readily cleaves into octahedral fragments. Common worldwide, with notable deposits in China, Mexico, South Africa, and the USA (Illinois, Kentucky).