mineral

Fluorite (Polished Egg)

Calcium Fluoride (CaF2)

AI-generated identification · may be incorrect

Hardness: 4 on the Mohs scale; Color: Deep purple, violet, clear/white, and yellowish banding; Luster: Vitreous to sub-vitreous; Crystal system: Isometric; Cleavage: Perfect octahedral in 4 directions; Specific gravity: 3.1 - 3.3.

Hardness: 4 on the Mohs scale
Color: Deep purple, violet, clear/white, and yellowish banding
Luster: Vitreous to sub-vitreous

Identified October 3, 2026More mineral →

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Physical properties

Formation & geological history

Formed predominantly through hydrothermal processes as veins or cavity fillings in rocks, often associated with metallic ores (lead, zinc, silver) or in limestone and dolostone environments.

Uses & applications

Commonly carved and polished into decorative shapes such as eggs, spheres, and figurines; used in gemstone collecting; industrial grade fluorite (fluorspar) is used as a flux in steelmaking and for manufacturing hydrofluoric acid and optical lenses.

Geological facts

Fluorite gave its name to the phenomenon of 'fluorescence' because many specimens glow brightly under ultraviolet light. It is one of the standard reference minerals on the Mohs hardness scale (defining hardness 4).

Field identification & locations

Can be identified by its distinctive octahedral cleavage, low hardness relative to quartz (easily scratched by a pocketknife), and zoning of purple, green, or yellow bands. Prominent localities include China, Mexico, England (Derbyshire Blue John), and Spain.