Fluorite

Physical Properties

Hardness: 4 (Mohs scale), Color: Green, blue, or purple (translucent), Luster: Vitreous/glassy, Crystal structure: Isometric/Cubic, Cleavage: Perfect octahedral (four directions), Specific gravity: 3.18

Formation & Geological History

Formed through hydrothermal activity, often in veins with metallic ores or in sedimentary carbonate rocks. It occurs across all geological ages but is often found in Mesozoic-Cenozoic deposits.

Uses & Applications

Used as a flux in steel and aluminum smelting, in the production of hydrofluoric acid, high-clarity camera lenses, and widely as a lapidary material for jewelry and ornamental carving.

Geological Facts

Fluorite is where the term 'fluorescence' comes from, as many specimens glow under ultraviolet light. It is often called the 'most colorful mineral in the world' due to the wide variety of possible hues.

Field Identification & Locations

Identify in the field by its distinct cleavage (often breaking into octahedrons), ability to be scratched by a knife but not a penny, and vitreous luster. Commonly found in China, Mexico, South Africa, and the USA (Illinois/Kentucky).

Identified on: 4/22/2026

Mode: Standard