Steinmetzite is a very rare phosphate mineral with formula Zn2Fe(PO4)2(OH)•3H2O. It was discovered among pegmatites of Hagendorf in Germany,Grey, I.E., Keck, E., Kampf, A.R., Mumme, W.G., MacRae, C.M., Gable, R.W., Glenn, A.M., and Davidson, C.J., 2015. Steinmetzite, IMA 2015-081. CNMNC Newsletter No. 28, December 2015, 1863; Mineralogical Magazine 79, 1859–1864 that are famous for rare phosphate minerals. Steinmetzite is chemically related to phosphophyllite and other zinc iron phosphates, namely plimerite and zinclipscombite.
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