AM_Dravite_1 Formula: Na.46 Ca.36 Mg2.04 V1.11 Cr.18 Fe.18 Al5.94 Ti.06 B3 Si5.64 O31 H3 Name: Dravite Unit cell: 15.967 15.967 7.191 90.0 90.0 120.0 , V=1587.69 Space group: R3M (160)

Foit F F , Rosenberg P E , American Mineralogist , 64 (1979) p.788-798, The structure of vanadium-bearing tourmaline and its implications regarding, tourmaline solid solutions