Spessartine
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R050063
      Novak G A, Gibbs G V
      American Mineralogist 56 (1971) 791-825
      The crystal chemistry of the silicate garnets
      sample Sp

      CELL PARAMETERS:  11.6359 11.6359 11.6359   90.000   90.000   90.000
      SPACE GROUP: Ia-3d     

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Si     0.37500   0.00000   0.25000     1.000     1.784
            Al     0.00000   0.00000   0.00000     1.000     0.412
            Mn     0.12500   0.00000   0.25000     0.870     0.489
            Fe     0.12500   0.00000   0.25000     0.130     0.489
            O      0.03510   0.04766   0.65261     1.000     0.395

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/- 10 +/- 10 +/- 10
            MAX. ABS. INTENSITY / VOLUME**2:      36.08567590    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                18.68          5.89        4.7503    2   1   1
                21.60          2.53        4.1139    2   2   0
                28.71          4.42        3.1098    3   2   1
                30.74         32.28        2.9090    4   0   0
                34.47        100.00        2.6019    4   2   0
                36.21          2.43        2.4808    3   3   2
                37.88         19.37        2.3752    4   2   2
                39.49         10.14        2.2820    4   3   1
                42.56         17.83        2.1244    5   2   1
                44.02          3.57        2.0570    4   4   0
                48.21         11.95        1.8876    6   1   1
                48.21         12.32        1.8876    5   3   2
                54.65         14.86        1.6795    4   4   4
                57.08         27.48        1.6136    6   4   0
                58.27          2.12        1.5834    5   5   2
                59.44         34.52        1.5549    6   4   2
                62.89          1.47        1.4778    6   5   1
                64.01          8.85        1.4545    8   0   0
                65.13          1.16        1.4323    7   4   1
                72.68          7.37        1.3009    8   4   0
                74.78         14.45        1.2696    8   4   2
                76.85          5.35        1.2404    6   6   4
                79.93          1.04        1.2002    9   3   2
                81.97          1.26        1.1754    9   4   1
                81.97          1.50        1.1754    8   5   3
                85.01          1.49        1.1410   10   2   0
                88.03          1.17        1.1094    7   6   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.