Ahrensite
      Yagi T, Marumo F, Akimoto S I
      American Mineralogist 59 (1974) 486-490
      Crystal structures of spinel polymorphs of Fe2SiO4 and Ni2SiO4
      Locality: synthetic
      _database_code_amcsd 0000404

      CELL PARAMETERS:    8.2340   8.2340   8.2340   90.000   90.000   90.000
      SPACE GROUP: Fd3m      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    558.255
      Density (g/cm3):      4.849
      MAX. ABS. INTENSITY / VOLUME**2:      65.32152693    
      RIR:      4.386
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                18.67         27.17        4.7539    1   1   1         8
                30.71         11.19        2.9112    2   2   0        12
                36.18        100.00        2.4826    3   1   1        24
                37.85         12.54        2.3770    2   2   2         8
                43.99         46.10        2.0585    4   0   0         6
                48.17         13.33        1.8890    3   3   1        24
                54.60          3.49        1.6808    4   2   2        24
                58.22          9.71        1.5846    3   3   3         8
                58.22         15.53        1.5846    5   1   1        24
                63.96         46.86        1.4556    4   4   0        12
                67.27          4.07        1.3918    5   3   1        48
                72.62          1.33        1.3019    6   2   0        24
                75.75          8.88        1.2557    5   3   3        24
                76.79          6.12        1.2413    6   2   2        24
                80.88          6.12        1.1885    4   4   4         8
                83.92          1.74        1.1530    7   1   1        24
                88.96          2.00        1.1003    6   4   2        48
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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.