mineral

Fluorite (Purple variety)

Calcium Fluoride (CaF2)

Hardness: 4 on Mohs scale; Color: Deep purple/violet (common in specimens like this); Luster: Vitreous (glassy); Crystal structure: Isometric (commonly cubic as seen in the specimen); Cleavage: Perfect octahedral; Specific gravity: 3.18

Hardness: 4 on Mohs scale
Color: Deep purple/violet (common in specimens like this)
Luster: Vitreous (glassy)

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal activity in veins where hot, mineral-rich fluids circulate through host rocks like limestone or granite. It often occurs as a gangue mineral in metallic ore deposits. Specimens can range from Precambrian to recent geological ages.

Uses & applications

Used as a flux in steel making, in the manufacture of hydrofluoric acid, and high-quality optical lenses. Purple fluorite is highly prized by mineral collectors and used for decorative carvings and jewelry beads.

Geological facts

Fluorite is the origin of the term 'fluorescence,' as many specimens glow under UV light. Pure fluorite is colorless; the purple hue is caused by structural defects or trace impurities. It is the state mineral of Illinois, USA.

Field identification & locations

Identify in the field by its cubic crystal habit and its ability to be scratched by a steel knife but not by a copper penny (Hardness 4). Commonly found in China, Mexico, South Africa, and the USA (Illinois/Kentucky fluorite district).