AM_Keiviite-(Yb)_1 Formula: (Yb1.42 Lu.22 Er.16 Tm.08 Y.06 Dy.04 Ho.02) Si2 O7 Name: Keiviite-(Yb) Unit cell: 4.715 8.87 6.805 90.0 102.01 90.0 , V=278.37 Space group: A12/M1 (12)

Yakubovich O V , Simonov M A , Voloshin A V , Pakhomovsky Y A , Soviet Physics Doklady , 31 (1986) p.930-932, Crystal structure of keivite Yb2[Si2O7], Locality: Kola Peninsula, Russia