mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on the Mohs scale. Color: Purple (as shown), but can be green, yellow, blue, or colorless. Luster: Vitreous (glassy). Crystal Structure: Isometric/Cubic. Cleavage: Perfect octahedral in four directions. Specific Gravity: 3.18.

Hardness: 4 on the Mohs scale
Luster: Vitreous (glassy)

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes, often in veins within limestone or associated with metallic ores. It can form at various geological ages from the Precambrian to more recent times.

Uses & applications

Industrial uses include smelting flux for steel, production of hydrofluoric acid, and high-clarity lenses for telescopes and cameras. Primarily used as a semi-precious gemstone and popular mineral specimen for collectors.

Geological facts

Fluorite is the most common mineral to exhibit 'fluorescence' under UV light, a property actually named after the mineral itself. It is the state mineral of Illinois.

Field identification & locations

Identify in the field by its distinct cubic crystal habit and its hardness (it can be scratched by a steel knife but not a copper penny). Common locations include China, Mexico, South Africa, and the Illinois-Kentucky Fluorspar District in the USA.