Ankerite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050272
      Reeder R J, Dollase W A
      American Mineralogist 74 (1989) 1159-1167
      Structural variation in the dolomite-ankerite solid-solution series: An X-ray,
      Mossbauer, and TEM study
      sample BM 1931-294

      CELL PARAMETERS:   4.811600   4.811600   16.04210   90.00000   90.00000   120.0000
      SPACE GROUP: R-3
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                24.03          7.91        3.7060    0   1   2
                30.87        100.00        2.8969    1   0   4
                33.42          3.13        2.6818    0   0   6
                35.21          3.23        2.5489    0   1   5
                37.30         12.60        2.4106    1   1   0
                41.05          7.97        2.1987    2  -1   3
                41.05         16.13        2.1987    1   1   3
                43.72          2.74        2.0703    0   2   1
                44.85         15.07        2.0207    2   0   2
                49.16          5.59        1.8530    0   2   4
                50.35         17.78        1.8121    0   1   8
                50.92          8.19        1.7928    1   1   6
                50.92         14.59        1.7928    2  -1   6
                58.77          1.69        1.5706    3  -1   1
                58.77          1.69        1.5706    2   1   1
                59.69          6.80        1.5486   -1   3   2
                59.69          2.90        1.5486    1   2   2
                63.28          4.12        1.4691    3  -1   4
                63.28          2.93        1.4691    2   1   4
                64.29          3.03        1.4485    2   0   8
                64.91          1.87        1.4360    2  -1   9
                64.91          1.23        1.4360    1   1   9
                65.90          1.77        1.4169   -1   3   5
                67.24          8.08        1.3918    3   0   0
                70.16          3.62        1.3409    0   0  12
                72.64          1.30        1.3010    2   1   7
                74.41          2.87        1.2744    0   2  10
                76.73          2.84        1.2416    1   2   8
                82.23          1.83        1.1718    1   1  12
                86.30          1.25        1.1267    3  -1  10
                86.30          1.06        1.1267    2   1  10
                87.64          1.48        1.1128    1   3   4
                87.64          1.48        1.1128    1   3   4
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.