AM_Hydroxy-dravite Formula: Na.457 Ca.246 K.012 Mg2.55 Al5.37 V.804 Cr.3 Ti.024 Si5.952 B3 O30.919 F.081 H.536 Name: Hydroxy-dravite Unit cell: 15.961 15.961 7.2214 90.0 90.0 120.0 , V=1593.21 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 sample TM507c, Locality: Olkhon (Lake Baikal), Siberia