AM_Biotite_3 Formula: K Fe1.392 Mg1.161 Ti.276 (Si2.792 Al1.208) O12 Name: Biotite Unit cell: 5.357 9.245 20.234 90.0 94.978 90.0 , V=998.32 Space group: C12/C1 (15)

Bohlen S R , Peacor D R , Essene E J , American Mineralogist , 65 (1980) p.55-62, Crystal chemistry of a metamorphic biotite and its significance in water, barometry, from Au Sable Forks, New York