AM_Hydroxy-dravite_3 Formula: Na.724 Ca.094 K.003 Al6.303 Mg2.064 Fe.576 Ti.063 Zn.012 V.003 Cr.003 Si5.982 B3 O30.954 F.046 H.572 Name: Hydroxy-dravite Unit cell: 15.9388 15.9388 7.205 90.0 90.0 120.0 , V=1585.17 Space group: R3M (160)

Bosi F , Lucchesi S , European Journal of Mineralogy , 16 (2004) p.335-344, Crystal chemistry of the schorl-dravite series, Note: Tourmaline TM235b, Locality: Beresov Mine, Siberia