mineral

Fluorite (Fluor-spar)

Calcium Fluoride (CaF2)

Hardness: 4 (Mohs scale); Color: Green, purple, and clear banding; Luster: Vitreous; Crystal Structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific Gravity: 3.18

Hardness: 4 (Mohs scale)
Color: Green, purple, and clear banding
Luster: Vitreous

Identified July 6, 2026More mineral →

Explore Fluorite (Fluor-spar) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 4 (Mohs scale); Color: Green, purple, and clear banding; Luster: Vitreous; Crystal Structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific Gravity: 3.18

Formation & geological history

Formed in hydrothermal veins usually through low-temperature precipitation, often found associated with metallic ores like lead and silver. It can occur in sedimentary rocks as a byproduct of volcanic Activity.

Uses & applications

Used in the manufacture of steel, enamel, and glass; also used as a flux. Clear varieties are used for high-performance optical lenses. Frequently polished for jewelry and ornamental carving.

Geological facts

Fluorite is the most colorful mineral in the world. It is the defining mineral for value 4 on the Mohs hardness scale. Many specimens exhibit fluorescence under ultraviolet light, a phenomenon named after the mineral itself.

Field identification & locations

Identify by its characteristic 4 directions of perfect cleavage and lower hardness (it can be scratched by a steel knife but not by a copper penny). It is commonly found in China, Mexico, and the USA (Illinois/Kentucky district).