What is "rosenbergite"

n. (context mineralogy English) A mineral with chemical formula AlF₃·3H₂O.

Rosenbergite is a mineral with the chemical formula Al F·3 HO. 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 3-3.5 on the Mohs Scale.