Fluorite

Physical Properties

Hardness: 4 on Mohs scale; Color: Mint green/purple; Luster: Vitreous; Crystal Structure: Isometric/Cubic; Cleavage: Perfect octahedral; Specific Gravity: 3.175–3.184.

Formation & Geological History

Formed through hydrothermal activity in veins, often associated with metallic ores. It can be found in sedimentary carbonates and igneous rocks. Geological age varies by deposit location.

Uses & Applications

Used as a flux in steel making, as a source for hydrofluoric acid, in high-performance optical lenses, and for decorative carvings or jewelry specimens.

Geological Facts

Fluorite is the origin of the term 'fluorescence' because many specimens glow under ultraviolet light. It is often called 'the most colorful mineral in the world'.

Field Identification & Locations

Identify in the field by its distinct cubic crystal habit, perfect cleavage into octahedrons, and the fact it can be easily scratched by a steel knife but scratches a penny. Common in China, Mexico, and the USA (Illinois/Kentucky).

Identified on: 4/19/2026

Mode: Standard