Langbanite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050664
      Moore P B, Sen Gupta P K, Le Page Y
      American Mineralogist 76 (1991) 1408-1425
      The remarkable langbanite structure type: Crystal structure, chemical
      crystallography and relation to some other cation close-packed structures

      CELL PARAMETERS:   11.55232   11.55232   11.14114   90.00000   90.00000   120.0000
      SPACE GROUP: P31m
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                15.33          7.91        5.7762    1   1   0
                15.90          4.11        5.5706    0   0   2
                17.28         13.07        5.1279    2  -1   1
                22.15          4.92        4.0097    1   1   2
                23.94          3.79        3.7137    0   0   3
                27.91          5.93        3.1948    3   0   1
                28.51          1.09        3.1287    2   1   2
                28.55          3.28        3.1238    1   1   3
                28.55          1.53        3.1238    2  -1   3
                30.94         15.41        2.8881    2   2   0
                31.24          1.09        2.8613    3   0   2
                31.99         34.35        2.7957    4  -2   1
                31.99         22.03        2.7957    2   2   1
                32.11         47.29        2.7853    0   0   4
                34.97         50.27        2.5640    2   2   2
                34.97         49.73        2.5640    4  -2   2
                35.76          1.10        2.5088    1   1   4
                39.50          5.24        2.2798    2   2   3
                40.08          1.04        2.2480    3   2   1
                40.45          2.45        2.2282    0   0   5
                41.32          2.80        2.1832    4   1   0
                42.15          2.17        2.1424    4   1   1
                42.15          1.15        2.1424    5  -1   1
                45.19          4.92        2.0048    2   2   4
                45.19         15.63        2.0048    4  -2   4
                47.91          1.39        1.8973    3   3   1
                48.32          2.50        1.8821    4   1   3
                49.14          1.67        1.8527    3   0   5
                50.09          1.43        1.8198    6  -3   2
                50.77          1.38        1.7969    5   1   0
                51.78          2.28        1.7642    2   2   5
                51.78          8.97        1.7642    4  -2   5
                53.27          2.62        1.7183    5  -1   4
                55.03         39.29        1.6674    6   0   0
                57.66          1.58        1.5974    6   0   2
                59.10         24.02        1.5619    2   2   6
                59.10          6.83        1.5619    4  -2   6
                63.16          1.04        1.4710    7  -2   3
                64.48          1.56        1.4440    4   4   0
                65.08          1.60        1.4321    8  -4   1
                65.08          2.60        1.4321    4   4   1
                65.15         24.03        1.4307    6   0   4
                66.88          6.55        1.3978    8  -4   2
                66.88          6.42        1.3978    4   4   2
                67.09          1.45        1.3939    2   2   7
                67.16          2.34        1.3926    0   0   8
                73.59          1.13        1.2861    4   1   7
                73.86          2.45        1.2820    4   4   4
                75.77          2.11        1.2544    4  -2   8
                78.94          1.83        1.2118    4   4   5
                85.03          1.95        1.1399    4   4   6
                85.03          5.40        1.1399    8  -4   6
                85.03          5.40        1.1399    8  -4   6
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.