AM_Vishnevite Formula: Na1.88 K1.29 Al3 Si3 S.29 O14.62 Name: Vishnevite Unit cell: 12.7228 12.7228 5.198 90.0 90.0 120.0 , V=728.67 Space group: P63 (173)

Della Ventura G , Bellatreccia F , Parodi G C , Camara F , Piccinini M , American Mineralogist , 92 (2007) p.713-721, Single-crystal FTIR and X-ray study of vishnevite, ideally, [Na6(SO4)][Na2(H2O)2](Si6Al6O24), Locality: Latium, Italy, Sample: Pi4