Mn₅(PO₃OH)(PO₄)₂.4H₂O

This sample of hureaulite is displayed in the Smithsonian Museum of Natural History. Hureaulite is a phosphate mineral of manganese with the composition Mn₅(PO₃OH)(PO₄)₂.4H₂O. The sample at left is about 12 cm across and is from Hagendorg pegmatite, Waidhaus, Bayern, Germany.