AM_Natroalunite Formula: (Na.58 K.42) Al3 S2 O14 H6 Name: Natroalunite Unit cell: 6.99 6.99 16.905 90.0 90.0 120.0 , V=715.32 Space group: R-3M (166)

Okada K , Hirabayashi J , Ossaka J , Neues Jahrbuch fur Mineralogie, Monatshefte , 1982 (1982) p.534-540, Crystal structure of natroalunite and crystal chemistry of the alunite group, Locality: Sonomi-dake, Makurazaki-city, Kagoshima Prefecture, Japan