Steinmetzite is a very rare phosphate mineral with formula Zn<sub>2</sub>Fe(PO<sub>4</sub>)<sub>2</sub>(OH)â¢3H<sub>2</sub>O. It was discovered among pegmatites of Hagendorf in Germany, that are famous for rare phosphate minerals. Steinmetzite is chemically related to phosphophyllite and other zinc iron phosphates, namely plimerite and zinclipscombite.