Prosopite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050668
      Pudovkina Z V, Chernitsova N M, Pyatenko Y A
      Journal of Structural Chemistry 14 (1973) 345-347
      Refinement of the crystalline structure of prosopite, CaAl2F4(OH)4

      CELL PARAMETERS:   6.705421   11.15015   7.364349   90.00000   94.91240   90.00000
      SPACE GROUP: C2/c
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                15.49          5.91        5.7308    1   1   0
                20.02          7.13        4.4390    0   2   1
                20.37        100.00        4.3636    1   1   1
                24.28          8.56        3.6686    0   0   2
                26.70          7.20        3.3404    2   0   0
                27.48         15.42        3.2479    1   3   0
                29.15         26.76        3.0646    0   2   2
                29.63         12.18        3.0168   -1   3   1
                30.57          1.15        2.9252    1   3   1
                31.23         12.45        2.8654    2   2   0
                32.12          1.30        2.7875    0   4   0
                32.72          4.31        2.7381   -2   2   1
                37.76          4.96        2.3831    1   3   2
                37.96          1.12        2.3709    2   0   2
                38.42          2.41        2.3433   -2   2   2
                38.97         23.44        2.3116   -1   1   3
                40.65         15.85        2.2195    0   4   2
                41.35          4.05        2.1838    3   1   0
                42.23         26.40        2.1402    2   4   0
                43.39          4.85        2.0856   -2   4   1
                44.24          1.23        2.0473   -1   5   1
                44.76          9.82        2.0250    2   4   1
                44.92          3.40        2.0180    1   5   1
                45.49          3.64        1.9941   -1   3   3
                46.58          9.21        1.9499   -3   1   2
                47.60         17.40        1.9103    3   3   0
                47.45          4.43        1.9158    1   3   3
                50.22         12.54        1.8164    3   3   1
                49.70         21.95        1.8343    0   0   4
                50.39          2.49        1.8109    3   1   2
                50.37          3.52        1.8114    1   5   2
                50.67          3.48        1.8015    0   6   1
                52.34          3.27        1.7478   -3   3   2
                53.55          1.50        1.7109    1   1   4
                54.97          5.13        1.6702    4   0   0
                55.47          3.37        1.6563   -2   4   3
                55.86          3.80        1.6456    3   3   2
                56.67          3.75        1.6240    2   6   0
                56.57          1.63        1.6265   -1   3   4
                56.75          1.20        1.6218   -1   5   3
                57.61          5.70        1.5997   -2   6   1
                57.63          3.79        1.5991   -2   2   4
                58.73          1.97        1.5718    2   6   1
                58.86          2.56        1.5685    2   4   3
                59.13          6.12        1.5622   -3   3   3
                58.82          3.03        1.5695    1   3   4
                59.66          1.80        1.5494    1   7   0
                60.85          4.15        1.5218    3   5   1
                60.84          4.73        1.5221   -1   7   1
                65.51          1.97        1.4244    4   2   2
                65.11          1.59        1.4321   -2   4   4
                67.50          1.18        1.3871    4   4   1
                67.14          1.85        1.3938    0   8   0
                66.95          1.27        1.3971    1   1   5
                68.21          5.32        1.3745   -3   3   4
                68.88          2.46        1.3628   -3   5   3
                69.24          5.46        1.3565    2   4   4
                70.97          2.19        1.3277    2   6   3
                73.60          4.29        1.2865    5   1   1
                74.18          1.18        1.2778   -4   4   3
                74.23          1.72        1.2771    3   3   4
                77.00          2.16        1.2378   -4   6   1
                76.71          2.06        1.2418   -2   6   4
                79.11          2.39        1.2101   -5   1   3
                80.01          2.44        1.1987    1   9   1
                80.27          1.02        1.1954   -1   7   4
                81.09          2.56        1.1855    4   0   4
                83.99          1.42        1.1517    0   6   5
                85.31          1.06        1.1372   -4   6   3
                86.51          1.53        1.1245    3   3   5
                87.43          1.05        1.1150    0  10   0
                89.78          1.66        1.0918   -6   0   2
                89.22          2.68        1.0972   -1   9   3
                89.22          2.68        1.0972   -1   9   3
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.