Gillespite
Pabst A
American Mineralogist 28 (1943) 372-390
Crystal structure of gillespite, BaFeSi4O10
7.495 7.495 16.050 90 90 90 P4/ncc
atom    x    y    z
Ba      0    0    0
Fe      0   .5 .090
Si   .270 .175 .155
O1   .215 .215  .25
O2   .465 .240 .140
O3   .135 .275 .090