AM_Schorl_11 Formula: Na.88 Ca.17 K.01 Fe2.43 Al6.09 Mg.12 Ti.06 Li.06 Mn.03 B3 Si6 (O31 H4) Name: Schorl Unit cell: 15.992 15.992 7.19 90.0 90.0 120.0 , V=1592.45 Space group: R3M (160)

Fortier S , Donnay G , The Canadian Mineralogist , 13 (1975) p.173-177, Schorl refinement showing composition dependence of the tourmaline structure