Fluorite (Rainbow or Multi-colored Fluorite)

Physical Properties

Hardness: 4 on Mohs scale; Color: Purple and green (bi-color); Luster: Vitreous (glassy); Crystal Structure: Cubic/Isometric; Cleavage: Perfect octahedral (four directions); Specific Gravity: 3.175–3.184.

Formation & Geological History

Formed in hydrothermal veins, often associated with metallic ores like lead and silver. It crystallizes as hot, mineral-rich fluids cool within rock fissures. It is found in geological environments ranging from the Paleozoic to the Cenozoic eras.

Uses & Applications

Used as a flux in steel making, in the production of hydrofluoric acid, high-performance telescope and camera lenses, and as a popular semi-precious stone for jewelry, carvings, and mineral collecting.

Geological Facts

Fluorite is the definition of level 4 on the Mohs hardness scale. It is famously fluorescent under UV light, a property named ('fluorescence') after the mineral itself. It is sometimes called 'the most colorful mineral in the world'.

Field Identification & Locations

Identify in the field by its distinct cleavage (often forming triangular or diamond-shaped faces when broken) and its relatively low hardness—it can be scratched by a steel knife but not by a copper penny easily. Common locations include China, Mexico, South Africa, and the Illinois-Kentucky district in the USA.

Identified on: 4/23/2026

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