AM_Hydroxy-dravite_2 Formula: Na.751 Ca.077 K.004 Al6.228 Mg2.085 Fe.6 Ti.084 Zn.009 V.003 Mn.003 Si5.988 B3 O30.996 F.004 H.632 Name: Hydroxy-dravite Unit cell: 15.9433 15.9433 7.2095 90.0 90.0 120.0 , V=1587.06 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 TM235a, Locality: Beresov Mine, Siberia