mineral

Fluorite (likely Fluorite on Quartz/Matrix)

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: Purple, green, yellow, or colorless (shows purple and yellowish hues here); Luster: Vitreous (glassy); Crystal Structure: Isometric/Cubic; Cleavage: Perfect octahedral; Specific Gravity: 3.18

Hardness: 4 on Mohs scale
Luster: Vitreous (glassy)

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins usually associated with metallic ores. While it can occur in rocks of all ages, it often precipitates from low-to-moderate temperature hot springs or fluids passing through limestone and dolostones.

Uses & applications

Industrial use as a flux in steel smelting, high-clarity lenses for telescopes and cameras, hydrofluoric acid production, and as a popular ornamental and collector gemstone.

Geological facts

Fluorite is where the term 'fluorescence' comes from, as many specimens glow under UV light. It is often called 'the most colorful mineral in the world.' It is the state mineral of Illinois, USA.

Field identification & locations

Identify in the field by its softness (it can be scratched by a knife but not by a copper penny), its octahedral cleavage (look for triangular shapes), and its characteristic purple-to-yellow color banding. Common locations include China, Mexico, England (Blue John), and the US (Illinois and Kentucky).

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

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Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

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