Mineral · Fluorite group
Fluorite
CaF2
Fluorite is calcium fluoride, the cubic and octahedral mineral in every colour from the Illinois–Kentucky fluorspar district (Illinois state mineral), Cumbria and Weardale (England), Hunan (China), Spain and Namibia. Perfect octahedral cleavage, hardness 4 and fluorescence under UV (the word comes from fluorite) identify it. Weardale green and Rogerley 'daylight fluorescent' fluorites are prized.
| Formula | CaF2 |
|---|---|
| IMA status | grandfathered |
| Crystal system | Cubic |
| Mohs hardness | 4 |
| Group | Fluorite group |
| Type locality | None (known since antiquity) |
| Streak | White |
| Specific gravity | 3.18 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Fakes and treatments
Cleaved octahedra sold as crystals are fragments, not grown crystals; Chinese fluorite is sometimes oiled to hide cleavage cracks or irradiated to deepen colour. Colour fades in sunlight.
Elsewhere
Cite this article
Stratum Study. "Fluorite" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/fluorite. Accessed 2026-09-20.
@misc{stratum-fluorite,
title = {Fluorite},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/fluorite}},
year = {2026},
note = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.