Weeksite Stohl F V, Smith D K American Mineralogist 66 (1981) 610-625 The crystal chemistry of the uranyl silicate minerals Locality: Anderson mine, Yavapai County, Arizona, USA _database_code_amcsd 0000839 7.106 17.900 7.087 90 90 90 Amm2 atom x y z U1 0 .198 0 Si 0 .130 .523 O1 .25 .307 .546 O2 0 .180 .693 O2b 0 .180 .307 O3 .194 .071 .487 O4 0 .429 .473