mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: typically green, purple, or clear; Luster: Vitreous; Crystal Structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific Gravity: 3.18

Hardness: 4 on Mohs scale
Color: typically green, purple, or clear
Luster: Vitreous

Identified June 8, 2026More mineral →

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Physical properties

Hardness: 4 on Mohs scale; Color: typically green, purple, or clear; Luster: Vitreous; Crystal Structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific Gravity: 3.18

Formation & geological history

Forms primarily in hydrothermal veins, often as a gangue mineral associated with metallic ores. It can also occur in sedentary rocks like limestone or as a late-stage crystallization in igneous rocks.

Uses & applications

Used as a flux for smelting, in the manufacture of certain glasses and enamels, for high-performance telescope and camera lenses, and as a popular ornamental gemstone for jewelry and carvings.

Geological facts

Fluorite is the origin of the term 'fluorescence' because many specimens glow under ultraviolet light. It is also known as 'the most colorful mineral in the world'.

Field identification & locations

Identified in the field by its 4.0 hardness (can be scratched by a knife but not a copper penny) and its characteristic octahedral cleavage. Commonly found in China, Mexico, and the USA (Illinois/Kentucky).