Green Fluorite in Host Rock

Physical Properties

Hardness: 4 (Mohs scale); Color: Pale green to emerald green crystals; Luster: Vitreous (glassy); Crystal Structure: Cubic/Isometric showing octahedral cleavage; Specific Gravity: 3.17 to 3.56.

Formation & Geological History

Formed in hydrothermal veins and through metasomatic processes where hot, fluorine-rich fluids react with calcium-bearing rocks (like limestone). Commonly occurs in various geological ages ranging from Paleozoic to Mesozoic.

Uses & Applications

Used as a flux in steelmaking (fluorospar), in the manufacture of hydrofluoric acid, in high-performance optical lenses, and as a popular lapidary material for decorative carvings and jewelry.

Geological Facts

Fluorite is the original source of the term 'fluorescence,' as many specimens glow strongly under UV light. It is often referred to as 'the most colorful mineral in the world' because of its wide range of hues.

Field Identification & Locations

Identify in the field by its distinct cubic crystal habits and its soft hardness (it can be scratched by a steel knife but not by a fingernail). Often found in Illinois (USA), China, Mexico, and England.

Identified on: 4/16/2026

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