data_global _chemical_name_mineral 'Dravite' loop_ _publ_author_name 'Vereshchagin O S' 'Rozhdestvenskaya I V' 'Frank-Kamenetskaya O V' 'Zolotarev A A' _journal_name_full 'European Journal of Mineralogy' _journal_volume 26 _journal_year 2014 _journal_page_first 309 _journal_page_last 321 _publ_section_title ; Ion substitutions and structural adjustment in Cr-bearing tourmalines Note: Sample 4 ; _database_code_amcsd 0020157 _chemical_compound_source 'Umba Valley, Tanzania' _chemical_formula_sum 'Ca.41 Na.43 Al6.15 Cr.18 Mg2.79 Si5.88 B3 O31 H3.56' _cell_length_a 15.921 _cell_length_b 15.921 _cell_length_c 7.194 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 1579.217 _exptl_crystal_density_diffrn 3.049 _symmetry_space_group_name_H-M 'R 3 m' loop_ _space_group_symop_operation_xyz 'x,y,z' '2/3+x,1/3+y,1/3+z' '1/3+x,2/3+y,2/3+z' 'x,x-y,z' '2/3+x,1/3+x-y,1/3+z' '1/3+x,2/3+x-y,2/3+z' '-y,-x,z' '2/3-y,1/3-x,1/3+z' '1/3-y,2/3-x,2/3+z' '-x+y,y,z' '2/3-x+y,1/3+y,1/3+z' '1/3-x+y,2/3+y,2/3+z' '-y,x-y,z' '2/3-y,1/3+x-y,1/3+z' '1/3-y,2/3+x-y,2/3+z' '-x+y,-x,z' '2/3-x+y,1/3-x,1/3+z' '1/3-x+y,2/3-x,2/3+z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_U_iso_or_equiv CaX 0.00000 0.00000 0.22400 0.41000 0.00730 NaX 0.00000 0.00000 0.22400 0.43000 0.00730 AlY 0.12314 0.06157 0.63700 0.67000 0.00920 CrY 0.12314 0.06157 0.63700 0.02000 0.00920 MgY 0.12314 0.06157 0.63700 0.31000 0.00920 AlZ 0.29759 0.26131 0.61076 0.67000 0.00640 CrZ 0.29759 0.26131 0.61076 0.02000 0.00640 MgZ 0.29759 0.26131 0.61076 0.31000 0.00640 SiT 0.19169 0.18984 0.00000 0.98000 0.00580 AlT 0.19169 0.18984 0.00000 0.02000 0.00580 B 0.10964 0.21928 0.45300 1.00000 0.00690 O-Hw 0.00000 0.00000 0.77100 0.89000 0.01260 O1w 0.00000 0.00000 0.77100 0.11000 0.01260 O2 0.06032 0.12064 0.48410 1.00000 0.01200 O-Hv 0.26140 0.13070 0.51060 0.89000 0.01520 O3v 0.26140 0.13070 0.51060 0.11000 0.01520 O4 0.09305 0.18610 0.07290 1.00000 0.01130 O5 0.18280 0.09140 0.09370 1.00000 0.01140 O6 0.19432 0.18431 0.77730 1.00000 0.00960 O7 0.28534 0.28487 0.07820 1.00000 0.00960 O8 0.20892 0.26967 0.43940 1.00000 0.01040