AM_Osumilite_3 Formula: K.9 Fe.41 Mg1.68 Si10.32 Al4.59 O30 Name: Osumilite Unit cell: 10.104 10.104 14.306 90.0 90.0 120.0 , V=1264.84 Space group: P6/MCC (192)

Armbruster T , Oberhansli R , American Mineralogist , 73 (1988) p.585-594, Crystal chemistry of double-ring silicates: Structural, chemical, and optical, variation in osumilites, Sample: Norway