Cummingtonite Yang H, Hirschmann M M American Mineralogist 80 (1995) 916-922 Crystal structure of P2_1/m ferromagnesian amphibole and the role of cation ordering and composition in the P2_1/m - C2/m transition in cummingtonite Sample: UH1, untreated _database_code_amcsd 0001752 9.5015 18.1289 5.3089 90 102.090 90 C2/m atom x y z occ Biso Fe1 0 .0869 .5 .200 .671 Mg1 0 .0869 .5 .800 .671 Fe2 0 .1771 0 .091 .693 Mg2 0 .1771 0 .903 .693 Al2 0 .1771 0 .006 .693 Fe3 0 0 0 .164 .521 Mg3 0 0 0 .836 .521 Fe4 0 .2589 .5 .906 .931 Mg4 0 .2589 .5 .051 .931 Ca4 0 .2589 .5 .043 .931 Si1 .2879 .0842 .2745 .561 Si2 .2979 .1688 .7812 .572 O1 .1142 .0869 .2092 .681 O2 .1232 .1721 .7193 .722 O3 .1133 0 .7068 .846 O4 .3805 .2454 .7689 .917 O5 .3514 .1313 .0646 1.036 O6 .3499 .1185 .5586 1.177 O7 .3434 0 .2699 1.026