data_global
_chemical_name_mineral 'Beryl'
loop_
_publ_author_name
'Gibbs G V'
'Breck D W'
'Meagher E P'
_journal_name_full 'Lithos'
_journal_volume 1 
_journal_year 1968
_journal_page_first 275
_journal_page_last 285
_publ_section_title
;
 Structural refinement of hydrous and anhydrous synthetic beryl,
 Al2(Be3Si6)O18 and emerald, Al1.9Cr0.1(Be3Si6)O18
 Note: hydrous beryl
;
_database_code_amcsd 0019467
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Al2 Be3 Si6 O19 H2'
_cell_length_a 9.213
_cell_length_b 9.213
_cell_length_c 9.206
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 676.712
_exptl_crystal_density_diffrn      2.726
_symmetry_space_group_name_H-M 'P 6/m c c'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-x+y,1/2+z'
  'x,x-y,1/2-z'
  '-x+y,-x,-z'
  'x-y,x,z'
  '-y,-x,1/2+z'
  'y,x,1/2-z'
  'y,-x+y,-z'
  '-y,x-y,z'
  'x-y,-y,1/2+z'
  '-x+y,y,1/2-z'
  'x,y,-z'
  '-x,-y,z'
  'x,x-y,1/2+z'
  '-x,-x+y,1/2-z'
  'x-y,x,-z'
  '-x+y,-x,z'
  'y,x,1/2+z'
  '-y,-x,1/2-z'
  '-y,x-y,-z'
  'y,-x+y,z'
  '-x+y,y,1/2+z'
  'x-y,-y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Al   0.66667   0.33333   0.25000   0.00190
Be   0.50000   0.00000   0.25000   0.00418
Si   0.38740   0.11590   0.00000   0.00139
O1   0.31010   0.23660   0.00000   0.00595
O2   0.49960   0.14580   0.14540   0.00355
Wat   0.00000   0.00000   0.25000   0.12665