Mineral

Fluorite (Rainbow, Purple-Blue Tumbled)

Calcium Fluoride (CaF2)

Hardness: 4 (Mohs scale); Color: Variegated blue, purple, and teal bands; Luster: Vitreous; Crystal structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific gravity: 3.175–3.184.

Hardness: 4 (Mohs scale)
Color: Variegated blue, purple, and teal bands
Luster: Vitreous

Identified March 16, 2026More mineral →

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Physical properties

Hardness: 4 (Mohs scale); Color: Variegated blue, purple, and teal bands; Luster: Vitreous; Crystal structure: Isometric (cubic); Cleavage: Perfect octahedral; Specific gravity: 3.175–3.184.

Formation & geological history

Formed through hydrothermal activity in veins where hot fluids circulate through fractures in limestone or igneous rocks. Most commercial deposits range from the Paleozoic to the Mesozoic eras.

Uses & applications

Used as a flux in steel making, in the production of hydrofluoric acid, and high-quality telescope lenses. Commonly polished into 'crystals' or beads for lapidary jewelry and metaphysical collecting.

Geological facts

Fluorite is the most colorful mineral in the world. The term 'fluorescence' was coined from this mineral because many specimens emit visible light under UV exposure. It is also an official state mineral of Illinois.

Field identification & locations

Identify in the field by its distinct cleavage planes, 'stepped' fractures, and soft surface (it can be scratched by a steel nail). Commonly found in China, Mexico, and the USA (Kentucky/Illinois district). Collectors look for vibrant banding and clarity.

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