Gahnite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R040027
      Andreozzi G B, Lucchesi S, Skogby H, Della Giusta A
      European Journal of Mineralogy 13 (2001) 391-402
      Compositional dependence of cation distribution in some synthetic
      (Mg,Zn)(Al,Fe)2O4 spinels
      Sample: Gah1a/a

      CELL PARAMETERS:   8.0988  8.0988  8.0988   90.000   90.000   90.000
      ALTERNATE SETTING FOR SPACE GROUP: Fd3m      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Mg     0.12500   0.12500   0.12500     0.225     0.616
            Zn     0.12500   0.12500   0.12500     0.647     0.616
            Al     0.12500   0.12500   0.12500     0.128     0.616
            Mg     0.50000   0.50000   0.50000     0.065     0.513
            Al     0.50000   0.50000   0.50000     0.935     0.513
            O      0.26339   0.26339   0.26339     1.000     0.624

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  7 +/-  7 +/-  7
            MAX. ABS. INTENSITY / VOLUME**2:      40.91282012    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                31.24         65.18        2.8634    2   2   0
                36.81        100.00        2.4419    3   1   1
                44.76         11.05        2.0247    4   0   0
                49.03          5.91        1.8580    3   3   1
                55.59         19.85        1.6532    4   2   2
                59.29          4.03        1.5586    3   3   3
                59.29         36.67        1.5586    5   1   1
                65.16         48.65        1.4317    4   4   0
                74.03          6.67        1.2805    6   2   0
                77.25          9.67        1.2351    5   3   3
                82.52          1.01        1.1690    4   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.