mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale. Color: Highly variable (purple and green shown here). Luster: Vitreous (glassy). Crystal structure: Isometric/Cubic. Cleavage: Perfect octahedral (four directions). Specific Gravity: 3.175–3.184.

Hardness: 4 on Mohs scale
Color: Highly variable (purple and green shown here)
Luster: Vitreous (glassy)

Identified April 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal activity in veins and as an accessory mineral in igneous rocks like granite. It often occurs as a gangue mineral associated with metallic ores. It can be found in geological environments ranging from sedimentary to metamorphic deposits.

Uses & applications

Used as a flux in steel and aluminum processing, in the manufacture of hydrofluoric acid, in high-performance telescopes and camera lenses (due to low dispersion), and as a popular semi-precious gemstone for jewelry and carvings.

Geological facts

Fluorite is famously fluorescent under UV light; the term 'fluorescence' was actually derived from this mineral. It is the official state mineral of Illinois. Pure fluorite is colorless; the vibrant colors are caused by impurities and radiation exposure.

Field identification & locations

Identify in the field by its distinct cubic crystal habit, octahedral cleavage, and softness (it can be scratched by a steel knife but not a copper coin). Commonly found in China, Mexico, South Africa, and the USA (Illinois/Kentucky). Collectors look for transparency and color zoning.