Windhoekite Chukanov N V, Britvin S N, Blass G, Belakovskiy D I, Van K V European Journal of Mineralogy 24 (2012) 171-179 Windhoekite, Ca2Fe3+3-x(Si8O20)(OH)4*10H2O, a new palygorskite-group mineral from the Aris phonolite, Namibia Note: the chemical formula for this mineral cannot be obtained from the crystal structure. The structure is missing two oxygens, and the OH positions were not given. Locality: Aris phonolite, Namibia _database_code_amcsd 0018919 14.319 17.825 5.242 90 103.5 90 C2/m atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) CaM3 .5 .3130 0 .62 .057 .063 .067 .043 0 .019 0 Mn2+M3 .5 .3130 0 .04 .057 .063 .067 .043 0 .019 0 CaM4 .5 .2300 .5 .37 .053 .065 .045 .050 0 .016 0 Mn2+M4 .5 .2300 .5 .03 .053 .065 .045 .050 0 .016 0 Fe3+M1 .5 .5 0 .0294 .050 .024 .018 0 .015 0 Fe3+M2 .5 .4126 .5 .88 .0301 .051 .023 .022 0 .019 0 Si1 .3001 .4162 .0314 .0222 .045 .010 .016 -.0034 .015 -.0011 Si2 .2987 .3313 .5262 .0272 .053 .010 .024 -.0030 .020 -.0001 O1 .4180 .4167 .1144 .026 .044 .012 .025 -.007 .016 -.002 O2 .4154 .3308 .5910 .036 .052 .023 .037 -.001 .017 -.003 O3 .25 .25 .5 .041 .092 .009 .029 -.017 .026 .005 O4 .5685 .5 .3644 .033 .043 .033 .033 0 .028 0 O5 .2576 .5 .0015 .031 .057 .008 .031 0 .019 0 O6 .2566 .3735 .2495 .031 .061 .018 .019 -.001 .022 .006 O7 .2598 .3745 .755 .032 .057 .009 .035 -.009 .023 -.006 Wat1 .106 .5 .361 .26 .27 .27 .33 0 .24 0 Wat2 .4064 .2302 .107 .132 .17 .12 .13 .019 .083 -.01 Wat3 .487 .106 .698 .87