Orthoclase Colville A A, Ribbe P H American Mineralogist 53 (1968) 25-37 The crystal structure of an adularia and a refinement of the structure of orthoclase Locality: St. Gotthard, Switzerland, known as Spencer B, variety adularia _database_code_amcsd 0000166 8.554 12.970 7.207 90 116.01 90 C2/m atom x y z occ Biso K .2835 0 .1369 2.26 Si1 .0094 .1843 .2247 .61 .83 Al1 .0094 .1843 .2247 .39 .83 Si2 .7079 .1176 .3443 .89 .65 Al2 .7079 .1176 .3443 .11 .65 OA1 0 .1448 0 1.7 OA2 .6354 0 .2840 1.3 OB .8276 .1448 .2277 2.2 OC .0351 .3116 .2590 1.6 OD .1818 .1254 .4075 1.2