Fluorite

Physical Properties

Hardness: 4 on Mohs scale; Color: Green, purple, clear, blue, or yellow; Luster: Vitreous (glassy); Crystal structure: Isometric/Cubic; Cleavage: Perfect octahedral; Specific gravity: 3.175–3.184.

Formation & Geological History

Forms primarily in hydrothermal veins, often as a gangue mineral associated with metallic ores. It can also be found in vugs in limestones and dolomites. It has been forming throughout various geological periods from the Precambrian to the Cenozoic.

Uses & Applications

Used as a flux in steel and aluminum smelting (it lowers the melting point), in the manufacturing of hydrofluoric acid, high-performance telescope and camera lenses, and widely used for ornamental jewelry and metaphysical collecting.

Geological Facts

Fluorite is the origin of the term 'fluorescence' because many specimens glow under ultraviolet light. It is often referred to as 'the most colorful mineral in the world' due to the wide variety of colors caused by impurities.

Field Identification & Locations

Identify in the field by its distinctive cubic crystals or triangular cleavage faces and its relatively low hardness (can be scratched by a steel knife but not a copper penny). Common locations include China, Mexico, South Africa, and the Illinois-Kentucky district in the USA.

Identified on: 4/20/2026

Mode: Standard