AM_Biotite_23 Formula: Si2.68 Al1.9 Fe1.38 Mg.73 Ti.14 Na.02 (K.96 Ca.03 Ba.01) O11.68 F.32 H1.56 Name: Biotite Unit cell: 5.339 9.232 10.208 90.0 100.3 90.0 , V=495.04 Space group: C12/M1 (12)

Brigatti M F , Frigieri P , Ghezzo c , Poppi L , American Mineralogist , 85 (2000) p.436-448, Crystal chemistry of Al-rich biotites coexisting with muscovites in, peraluminous granites, Sample: GFS15a