Fluorite (Rainbow Fluorite)

Physical Properties

Hardness: 4 on the Mohs scale; Color: Multi-colored bands (purple, green, blue, clear); Luster: Vitreous (glassy); Crystal structure: Isometric/Cubic; Cleavage: Perfect octahedral; Specific gravity: 3.175–3.184.

Formation & Geological History

Formed through hydrothermal activity, often in veins where it precipitates from hot, mineral-rich fluids passing through rock fractures. It is commonly found in sedimentary rocks and associated with lead and zinc ores.

Uses & Applications

Used industrially as a flux for smelting steel/aluminum, in the manufacturing of hydrofluoric acid, and for high-performance optical lenses. In this polished 'tower' form, it is primarily used for decorative purposes, collecting, and metaphysical displays.

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' due to the wide variety of hues it can display.

Field Identification & Locations

Identify in the field by its distinct cubic crystal habit, octahedral cleavage, and softness (it can be scratched by a steel knife but not a copper penny). Common locations include China, Mexico, South Africa, and Illinois, USA.

Identified on: 4/26/2026

Mode: Standard