mineral

Polished blue fluorite egg

Fluorite (calcium fluoride, CaF₂)

AI-generated identification · may be incorrect

Typically translucent to transparent blue-green with vitreous luster and visible cubic cleavage; Mohs hardness 4, specific gravity about 3.18, and cubic crystal structure. The smooth egg shape is human-polished.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in hydrothermal veins and carbonate-hosted deposits, often with quartz, calcite, or metallic ores; individual specimens may range from Paleozoic to younger Cenozoic mineralization. Common sources include China, Mexico, England, and the United States.

Uses & applications

Used as a flux in steel and aluminum production, hydrofluoric-acid feedstock, and ornamental or lapidary material; polished eggs are primarily decorative and collectible.

Geological facts

Blue fluorite commonly owes its color to trace elements, defects, or radiation exposure, and color may fade in strong sunlight. Cleavage is exceptionally perfect in four directions, so it can chip despite its attractive polish.

Field identification & locations

Identify it by its cool glassy luster, relatively low hardness, cubic cleavage, and often banded or cloudy zoning; it should not scratch glass reliably. Similar blue calcite is softer and lacks fluorite’s characteristic cubic cleavage.