mineral

Fluorite

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: Blue, purple, green, yellow, or clear; Luster: Vitreous (glassy); Crystal structure: Isometric (cubic); Cleavage: Perfect octahedral in four directions; Specific gravity: 3.175 to 3.184.

Hardness: 4 on Mohs scale
Color: Blue, purple, green, yellow, or clear
Luster: Vitreous (glassy)

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a hydrothermal mineral in veins, often in association with metallic ores like lead and silver. It can also occur in various sedimentary and igneous environments. Specimens can range from hundreds of millions of years old to relatively recent geological formations.

Uses & applications

Used as a flux in steelmaking and aluminum production; used to make hydrofluoric acid and opal glass; high-clarity specimens are used for specialized optical lenses. In jewelry, it is often used for beads or cabochons, though it is soft. Highly popular among mineral collectors.

Geological facts

Fluorite is the origin of the term 'fluorescence,' as many specimens glow under UV light. It is often called 'the most colorful mineral in the world' because of its vast range of hues caused by elemental impurities.

Field identification & locations

Identify in the field by its softness (can be scratched by a steel knife but not a copper penny) and its distinct octahedral cleavage. Common locations include China, Mexico, South Africa, and the United States (specifically Illinois and Kentucky). Collectors look for transparency and color zoning.