AM_Armenite_1 Formula: Ba Ca2 Si9 Al6 O32.11 H4 Name: Armenite Unit cell: 18.66 10.697 13.874 90.0 90.0 90.0 , V=2769.33 Space group: PNC2 (30)

Armbruster T , American Mineralogist , 84 (1999) p.92-101, Si,Al ordering in the double-ring silicate armenite, BaCa2Al6Si9O30.2H2O:, A single-crystal X-ray and 29Si MAS NMR study