mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on the Mohs scale. Color: Highly variable, commonly purple, green, blue, yellow, or clear. Luster: Vitreous to sub-vitreous. Crystal Structure: Isometric (cubic). Cleavage: Perfect octahedral cleavage in four directions. Specific gravity: 3.18.

Hardness: 4 on the Mohs scale
Luster: Vitreous to sub-vitreous

Identified August 6, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, often associated with metallic ores like lead and zinc, as well as in cavities in limestone and dolomite. Geological age varies widely depending on the deposit.

Uses & applications

Used in metallurgy as a flux, in the manufacture of opalescent glass, enamels, and hydrofluoric acid, as well as in optical equipment, carvings, and collector gemstones.

Geological facts

Fluorite is the defining mineral for a hardness of 4 on the Mohs scale. It gave the term 'fluorescence' its name because many specimens glow strongly under ultraviolet light due to impurities like yttrium.

Field identification & locations

Identified by its relatively low hardness (easily scratched with a knife but not a copper coin), perfect octahedral cleavage, and often vibrant purple or green coloring. Found worldwide, with major deposits in China, Mexico, South Africa, and the USA.