mineral

Fluorite

Calcium Fluoride (CaF2)

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

Hardness: 4 on Mohs scale
Color: Variable, commonly green, purple, or blue
Luster: Vitreous (glassy)

Identified July 2, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins often associated with metallic minerals like lead and silver. It can also occur in vugs within sedimentary rocks like limestone. Geological age varies by location, from Precambrian to recent.

Uses & applications

Used as a flux in steel making, in the manufacture of hydrofluoric acid, in high-performance telescope and camera lenses, and as a popular ornamental gemstone for collectors.

Geological facts

Fluorite was the original source for the phenomenon of fluorescence, where minerals glow under ultraviolet light. Pure fluorite is colorless; its vibrant colors are caused by various impurities.

Field identification & locations

Identify in the field by its distinct cubic crystals or octahedral cleavage, relatively low hardness (can be scratched by a knife but not a penny), and its tendency to glow under UV light. Common locations include China, Mexico, and the Illinois-Kentucky fluorspar district.