Titanite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R050039
      Taylor M, Brown G E
      American Mineralogist 61 (1976) 435-447
      High-temperature structural study of the P2_1/a - A2/a phase transition in
      synthetic titanite, CaTiSiO5
      T = 25 deg C

      CELL PARAMETERS:   7.0510  8.7478  6.5810   90.000  113.720   90.000
      SPACE GROUP: P2_1/a    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Ca     0.24390   0.41840   0.25130     1.000     1.260
            Ti     0.51240   0.25570   0.74980     1.000     0.600
            Si     0.74940   0.43270   0.24930     1.000     0.400
            O      0.74970   0.32120   0.74980     1.000     0.700
            O      0.90950   0.31750   0.43290     1.000     0.750
            O      0.08700   0.18510   0.06260     1.000     0.600
            O      0.38130   0.45860   0.64480     1.000     0.520
            O      0.61780   0.03810   0.85200     1.000     0.730

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  5 +/-  8 +/-  5
            MAX. ABS. INTENSITY / VOLUME**2:      16.06295950    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                17.88         23.12        4.9620    0   1   1
                20.30          1.32        4.3739    0   2   0
                27.53        100.00        3.2405   -2   1   1
                27.64          3.19        3.2277    2   0   0
                29.65         73.29        3.0125    0   0   2
                31.43          6.59        2.8463   -2   0   2
                34.15          1.41        2.6253   -1   2   2
                34.16         63.47        2.6247    0   3   1
                34.54         45.92        2.5971    2   2   0
                37.71          3.73        2.3856   -2   2   2
                37.96          4.32        2.3704    2   1   1
                39.25         18.17        2.2951    1   3   1
                39.76         10.94        2.2673   -3   1   1
                40.31          4.53        2.2373   -2   3   1
                41.28          2.36        2.1869    0   4   0
                42.69         10.08        2.1179   -1   1   3
                43.18          4.39        2.0951    1   2   2
                43.68         17.25        2.0723   -2   1   3
                43.70         10.30        2.0713    1   4   0
                45.76          2.12        1.9829   -3   2   2
                46.39          7.22        1.9574    0   1   3
                48.38          1.23        1.8814    2   3   1
                48.96          3.31        1.8604    2   0   2
                50.40          9.91        1.8105    2   4   0
                51.59          1.29        1.7715    3   1   1
                51.65          1.37        1.7698    0   4   2
                52.46         12.33        1.7443   -4   0   2
                52.79         13.21        1.7342   -2   4   2
                53.21          2.80        1.7216   -2   3   3
                53.53         18.60        1.7120    2   2   2
                53.58          3.56        1.7104   -4   1   1
                54.90          1.42        1.6724   -1   5   1
                55.56         24.79        1.6540    0   3   3
                57.07          4.23        1.6138    4   0   0
                59.07         13.61        1.5639   -2   5   1
                60.23          7.20        1.5366   -2   2   4
                61.57          5.23        1.5063    0   0   4
                62.00         17.37        1.4968   -4   3   1
                62.40          1.17        1.4881    1   3   3
                63.84          2.27        1.4580    0   6   0
                64.65          4.77        1.4417    2   1   3
                65.44          7.79        1.4262    2   5   1
                65.60         11.61        1.4231   -4   0   4
                65.92          2.31        1.4170    2   4   2
                66.16          7.06        1.4124   -4   3   3
                69.49          9.29        1.3527   -2   5   3
                71.93          3.00        1.3127   -2   4   4
                71.95          6.83        1.3124    0   6   2
                72.68          1.10        1.3009   -2   1   5
                74.17          7.92        1.2784    4   3   1
                77.53          4.22        1.2313    4   0   2
                78.42          1.07        1.2194   -3   6   2
                80.48          1.02        1.1933    2   0   4
                81.16          1.21        1.1851   -3   3   5
                84.08          1.95        1.1513    2   2   4
                85.58          3.13        1.1348   -4   3   5
                86.83          1.50        1.1217    2   5   3
                87.12          1.47        1.1187   -4  -6   2
                87.54          3.18        1.1144    2   7   1
                87.61          4.78        1.1137    0   3   5
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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.