Rosenbergite is a mineral with the chemical formula AlF<sub>3</sub>÷3H<sub>2</sub>O. It is a trihydrate of aluminium fluoride.
It is colorless. Its crystals are tetragonal to dipyramidal. It is named after Philip E. Rosenberg, a United States geochemist. It is found in the Celtine Mine in Tuscany, Italy and Mount Erebus, Ross Island, Antarctica. It is not radioactive. Rosenbergite is rated 3âÂÂ3.5 on the Mohs Scale.