mineral
Green glassy mineral fragment, possibly fluorite
Fluorite (calcium fluoride, CaF₂), tentative identification
AI-generated identification · may be incorrectSmall translucent vivid-green fragment with a vitreous luster and likely irregular fracture; fluorite has Mohs hardness 4, cubic crystals, perfect octahedral cleavage, and specific gravity about 3.18. The image is insufficient to exclude man-made green glass or another mineral such as prehnite, peridot, or uranium-bear…
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Physical properties
Small translucent vivid-green fragment with a vitreous luster and likely irregular fracture; fluorite has Mohs hardness 4, cubic crystals, perfect octahedral cleavage, and specific gravity about 3.18. The image is insufficient to exclude man-made green glass or another mineral such as prehnite, peridot, or uranium-bearing material.
Formation & geological history
Green fluorite forms in hydrothermal veins, commonly with quartz, calcite, and barite, and is generally Paleozoic to younger depending on the deposit. Fluorite is geologically plausible around central Hesse, Germany, though the specimen cannot be localized confidently from the photo.
Uses & applications
Fluorite is used as a flux in steel and aluminum production, in hydrofluoric-acid manufacture, and as a collector or gemstone specimen; transparent pieces may be faceted, though they are relatively soft. Common fragments are usually worth about $1–$10; attractive crystals or gem-quality material may range from $20–$200+.
Geological facts
Strong green color can result from trace rare-earth elements or radiation-related defects. Fluorite commonly fluoresces blue, violet, or green under ultraviolet light.
Field identification & locations
Check for cubic/octahedral cleavage, hardness below glass, and density; a scratch test and UV response are useful but not definitive. If it has perfectly smooth conchoidal fracture and no cleavage, green glass is more likely; do not heat or abrade it until confirmed.
