AM_Jahnsite Formula: Na Fe3 Mg2 P4 O26 H18 Name: Jahnsite Unit cell: 15.0811 7.1403 9.8299 90.0 110.445 90.0 , V=991.84 Space group: P12/A1 (13)

Kampf A R , Steele I M , Loomis T A , American Mineralogist , 93 (2008) p.940-945, Jahnsite-(NaFeMg), a new mineral from the Tip Top mine, Custer County,, South Dakota: Description and crystal structure, Locality: Tip Top mine, Custer County, South Dakota