Citation: Ohta, T.; Takeuchi, Y.; Takeda, H. (1982). Mica polytypism: similarities in the crystal structures of coexisting 1M and 2M1 oxybiotite. American Mineralogist, 67, pp. 298-310.
Formula: Al1.324 F0.16 Fe0.862 H0.3 K Mg1.638 O11.84 Si2.84 Ti0.336