data_global _chemical_name_mineral 'Beryl' loop_ _publ_author_name 'Hazen R M' 'Au A Y' 'Finger L W' _journal_name_full 'American Mineralogist' _journal_volume 71 _journal_year 1986 _journal_page_first 977 _journal_page_last 984 _publ_section_title ; High-pressure crystal chemistry of beryl (Be3Al2Si6O18) and euclase (BeAlSiO4OH) Sample: Pressure = 57 kbar ; _database_code_amcsd 0001043 _chemical_formula_sum 'Be3 Al2 Si6 O18' _cell_length_a 9.127 _cell_length_b 9.127 _cell_length_c 9.064 _cell_angle_alpha 90 _cell_angle_beta 90 _cell_angle_gamma 120 _cell_volume 653.893 _exptl_crystal_density_diffrn 2.730 _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 Be 0.50000 0.00000 0.25000 0.01013 Al 0.33333 0.66667 0.25000 0.01267 Si 0.38930 0.11660 0.00000 0.01203 O1 0.31070 0.23660 0.00000 0.00380 O2 0.49920 0.14520 0.14700 0.00912