Anhydrite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R040012
      Hawthorne F C, Ferguson R B
      The Canadian Mineralogist 13 (1975) 289-292
      Anhydrous sulphates. II. Refinement of the crystal structure of anhydrite

      CELL PARAMETERS:   7.0040  6.9930  6.2405   90.000   90.000   90.000
      SPACE GROUP: Amma      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Ca     0.75000   0.00000   0.34760     1.000     0.654
            S      0.25000   0.00000   0.15556     1.000     0.551
            O      0.25000   0.16990   0.01620     1.000     0.986
            O      0.08190   0.00000   0.29750     1.000     0.939

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  6 +/-  6 +/-  5
            MAX. ABS. INTENSITY / VOLUME**2:      15.79619559    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                22.94          8.83        3.8775    1   1   1
                25.43        100.00        3.5020    2   0   0
                25.47         98.24        3.4965    0   2   0
                28.61          3.94        3.1202    0   0   2
                31.39         59.83        2.8502    1   0   2
                31.98          5.88        2.7987    2   1   1
                36.31         13.91        2.4743    2   2   0
                38.65          2.42        2.3297    2   0   2
                38.68         33.74        2.3280    0   2   2
                40.85         38.67        2.2092    1   2   2
                41.35         12.14        2.1836    0   3   1
                43.36         12.23        2.0870    3   1   1
                45.49          8.95        1.9938    0   1   3
                46.86          6.33        1.9387    2   2   2
                48.71         27.73        1.8693    3   0   2
                49.17          6.04        1.8529    2   3   1
                52.24         10.27        1.7510    4   0   0
                52.33         10.51        1.7483    0   4   0
                55.76         27.56        1.6485    3   2   2
                57.82          4.74        1.5948    3   3   1
                59.00          3.63        1.5656    4   2   0
                59.06          3.88        1.5642    2   4   0
                60.72          5.45        1.5252    0   4   2
                60.83          1.01        1.5228    1   0   4
                61.16          1.25        1.5153    1   3   3
                62.30          9.81        1.4902    1   4   2
                65.50          1.55        1.4251    2   0   4
                65.52          3.98        1.4247    0   2   4
                65.82          1.76        1.4189    2   3   3
                66.86          1.91        1.3994    4   2   2
                66.92          1.46        1.3983    2   4   2
                67.03          3.90        1.3961    1   2   4
                68.71          1.40        1.3661    4   3   1
                71.49          9.03        1.3197    2   2   4
                72.93          3.14        1.2972    3   0   4
                74.21          3.40        1.2779    5   0   2
                74.28          9.97        1.2769    3   4   2
                77.09          1.88        1.2372    4   4   0
                78.68          7.38        1.2162    3   2   4
                79.93          4.33        1.2003    5   2   2
                82.66          3.99        1.1673    6   0   0
                82.82          3.95        1.1655    0   6   0
                82.95          1.71        1.1640    0   4   4
                84.35          1.89        1.1483    1   4   4
                88.25          3.36        1.1073    6   2   0
                88.39          3.34        1.1059    2   6   0
                88.47          4.58        1.1051    4   2   4
                88.52          4.35        1.1046    2   4   4
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       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.