AM_Perhamite Formula: Ca2.7 Sr.3 P4 Al7.7 Si3 O45.862 H12.68 Name: Perhamite Unit cell: 7.021 7.021 20.218 90.0 90.0 120.0 , V=863.11 Space group: P-3M1 (164)

Mills S , Mumme G , Grey I , Bordet P , Mineralogical Magazine , 70 (2006) p.201-209, The crystal structure of perhamite, Note: H positions unknown, Locality: Emmons mine, Greenwood, Maine