data_global
_chemical_name_mineral 'Dravite'
loop_
_publ_author_name
'Schmetzer K'
'Nuber B'
'Abraham K'
_journal_name_full 'Neues Jahrbuch fur Mineralogie, Abhandlungen'
_journal_volume 136 
_journal_year 1979
_journal_page_first 93
_journal_page_last 112
_publ_section_title
;
 Zur Kristallchemie Magnesium-reicher Turmaline
;
_database_code_amcsd 0019011
_chemical_compound_source 'Gerevi Hills, Tanzania'
_chemical_formula_sum 'Na.6 Ca.29 K.02 Mg2.37 Al6.63 Si6 B3 O31 H3.75'
_cell_length_a 15.923
_cell_length_b 15.923
_cell_length_c 7.201
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 1581.151
_exptl_crystal_density_diffrn      3.035
_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
Na   0.00000   0.00000   0.85760   0.60000
Ca   0.00000   0.00000   0.85760   0.29000
K   0.00000   0.00000   0.85760   0.02000
Mg   0.06250  -0.06250   0.45810   0.79000
Al   0.06250  -0.06250   0.45810   0.21000
Al   0.26170   0.29780   0.47900   1.00000
Si   0.18990   0.19190   0.09070   1.00000
B  -0.10960   0.10960   0.63490   1.00000
O1   0.00000   0.00000   0.31750   0.25000
O-H1   0.00000   0.00000   0.31750   0.75000
O2  -0.06070   0.06070   0.60510   1.00000
O-H3   0.13260  -0.13260   0.57740   1.00000
O4  -0.09330   0.09330   0.02040   1.00000
O5   0.09160  -0.09160  -0.00110   1.00000
O6   0.18590   0.19590   0.31140   1.00000
O7   0.28460   0.28510   0.01110   1.00000
O8   0.26990   0.10930   0.64850   1.00000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Na 0.01940 0.01940 0.02300 0.00970 0.00000 0.00000
Ca 0.01940 0.01940 0.02300 0.00970 0.00000 0.00000
K 0.01940 0.01940 0.02300 0.00970 0.00000 0.00000
Mg 0.00300 0.00300 0.01310 0.00040 0.00210 -0.00210
Al 0.00300 0.00300 0.01310 0.00040 0.00210 -0.00210
Al 0.00340 0.00300 0.00530 0.00160 -0.00010 0.00020
Si 0.00200 0.00190 0.00560 0.00100 0.00020 0.00020
B 0.00350 0.00350 0.00690 0.00210 0.00030 -0.00030
O1 0.00910 0.00910 0.00980 0.00460 0.00000 0.00000
O-H1 0.00910 0.00910 0.00980 0.00460 0.00000 0.00000
O2 0.00960 0.00960 0.01060 0.00740 0.00000 0.00000
O-H3 0.01040 0.01040 0.00640 -0.00040 -0.00040 0.00040
O4 0.00530 0.00530 0.01120 -0.00090 -0.00080 0.00080
O5 0.00480 0.00480 0.01160 -0.00220 -0.00050 0.00050
O6 0.00760 0.00740 0.01100 0.00430 0.00150 0.00150
O7 0.00390 0.00400 0.01040 0.00020 0.00100 0.00120
O8 0.00680 0.00260 0.01340 0.00200 -0.00220 -0.00040