AM_Johannsenite
Formula: Ca Mn Si2 O6
Name: Johannsenite
Unit cell: 9.978 9.156 5.293 90.0 105.48 90.0 , V=466.02
Space group: C12/C1 (15)

Freed R L , Peacor D R , American Mineralogist , 52 (1967) p.709-720, Refinement of the crystal structure of johannsenite