Fluorite

Physical Properties

Hardness: 4 on Mohs scale; Color: typically green, purple, yellow, or clear; Luster: vitreous (glassy); Crystal system: isometric/cubic; Cleavage: perfect octahedral in 4 directions; Specific gravity: 3.175–3.184.

Formation & Geological History

Formed in hydrothermal veins through heating of groundwater or within igneous rocks like granites. It occurs across all geological ages in carbonate rocks and near metallic ore deposits.

Uses & Applications

Used industrially as a flux for steelmaking, in the manufacture of hydrofluoric acid, high-performance telescope lenses, and widely as a semi-precious gemstone or decorative mineral for collectors.

Geological Facts

The term 'fluorescence' was derived from fluorite because many specimens exhibit a strong glow under ultraviolet light. It is often called 'the most colorful mineral in the world'.

Field Identification & Locations

Identified in the field by its distinct colors, inability to scratch glass but ability to scratch a copper coin, and its perfect 4-way cleavage. Common locations include China, Mexico, South Africa, and the USA (Illinois, Kentucky).

Identified on: 5/9/2026

Mode: Standard