Fluorine is a highly reactive chemical, which is why it is generally not found in its elemental form in nature. At least that was the received wisdom. New direct evidence puts to rest a debate that has lasted for two centuries regarding special fluorite mineral, the "fetid fluorite" or "antozonite"; crush the mineral and it produces a foul odor. Using, fluorine-19 nuclear magnetic (NMR) spectroscopy, researchers at the Technische Universitaet Muenchen (TUM) and the Ludwig-Maximilians-University Munich (LMU) in Germany have successfully identified natural elemental fluorine trapped within tiny inclusions found in the mineral and separated from calcium ions with which it would otherwise react.
The stinky fluorine problem