AM_Hydroxy-dravite_5 Formula: Na.714 Ca.099 K.004 Al6.387 Mg2.151 Fe.486 Ti.039 Zn.012 V.003 Si5.922 B3 O30.995 F.004 H.633 Name: Hydroxy-dravite Unit cell: 15.9355 15.9355 7.2002 90.0 90.0 120.0 , V=1583.46 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 TM233g, Locality: Zillerthal, Tyrol, Austria