Dravite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050304
      Hawthorne F C, MacDonald D J, Burns P C
      American Mineralogist 78 (1993) 265-270
      Reassignment of cation site occupancies in tourmaline: Al-Mg disorder in the
      crystal structure of dravite

      CELL PARAMETERS:   15.94700   15.94700   7.214000   90.00000   90.00000   120.0000
      SPACE GROUP: R3m
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                13.93         21.90        6.3772    1   0   1
                17.83         28.31        4.9872    0   2   1
                19.25          5.98        4.6200    3   0   0
                21.03         91.34        4.2325    2   1   1
                22.26         94.18        4.0011    2   2   0
                25.66         74.65        3.4765    0   1   2
                26.33         11.18        3.3892    1   3   1
                28.02          2.27        3.1886    2   0   2
                28.64          3.74        3.1208    4   0   1
                29.57          8.13        3.0245    4   1   0
                30.20         72.95        2.9621    1   2   2
                30.78         10.15        2.9076    3   2   1
                33.63          2.28        2.6674    3   3   0
                34.20          9.32        2.6243    3   1   2
                34.71        100.00        2.5861    0   5   1
                36.04          1.93        2.4936    0   4   2
                36.54          5.26        2.4608    2   4   1
                37.59         13.38        2.3942    0   0   3
                37.81         15.62        2.3807    2   3   2
                38.29         17.34        2.3521    5   1   1
                39.01          2.97        2.3100    6   0   0
                40.67          1.61        2.2194    5   2   0
                41.16         10.45        2.1944    5   0   2
                41.60         18.20        2.1719    4   3   1
                42.55         10.05        2.1257    0   3   3
                42.55          8.20        2.1257    3   0   3
                42.75          4.00        2.1162    4   2   2
                44.10         13.75        2.0545    2   2   3
                44.29         44.25        2.0459    1   5   2
                44.71          6.06        2.0277    1   6   1
                45.35          5.64        2.0005    4   4   0
                47.26         38.47        1.9240    3   4   2
                47.66          2.61        1.9088    7   0   1
                47.66          1.77        1.9088    3   5   1
                48.51          5.54        1.8772    1   4   3
                49.08          7.61        1.8567    6   2   1
                49.67          2.12        1.8358    7   1   0
                51.32          2.79        1.7808    1   0   4
                51.29          5.65        1.7817    3   3   3
                52.67          1.46        1.7383    0   2   4
                52.81          1.81        1.7339    0   7   2
                52.81          1.43        1.7339    5   3   2
                53.17          1.05        1.7228    5   4   1
                54.13          4.12        1.6946    2   6   2
                55.27         14.41        1.6624    0   6   3
                55.27          5.21        1.6624    6   0   3
                55.79         14.86        1.6481    2   7   1
                57.84          2.76        1.5943    4   0   4
                57.60         16.43        1.6004    5   5   0
                57.97          2.82        1.5910    4   5   2
                58.32          2.16        1.5823    8   1   1
                59.09          1.28        1.5636    3   2   4
                59.56          5.89        1.5523    4   6   1
                60.08          5.03        1.5400    9   0   0
                60.45          6.27        1.5316    7   2   2
                60.78          1.25        1.5239    7   3   1
                61.53         17.46        1.5071    0   5   4
                61.30          4.71        1.5123    8   2   0
                62.73          4.54        1.4810    2   4   4
                62.86          1.63        1.4784    1   8   2
                63.92         16.26        1.4563    5   1   4
                63.90          5.11        1.4568    1   7   3
                63.90          1.44        1.4568    7   1   3
                64.05          4.15        1.4538    6   4   2
                65.30          3.87        1.4289    0   1   5
                64.87          4.88        1.4372    7   4   0
                65.55          7.27        1.4241    6   5   1
                65.55          2.22        1.4241    1   9   1
                66.27         13.92        1.4104    4   3   4
                66.24          4.68        1.4108    6   3   3
                66.24          1.73        1.4108    3   6   3
                67.86          1.59        1.3810    3   8   1
                69.00         12.06        1.3609   10   0   1
                69.82          2.83        1.3469    5   6   2
                71.02          3.79        1.3270    0   4   5
                70.83          1.05        1.3301    7   0   4
                70.83          2.39        1.3301    3   5   4
                70.81          4.51        1.3305    5   5   3
                70.62          4.50        1.3337    6   6   0
                72.14          1.98        1.3091    2   3   5
                71.95          1.24        1.3121    6   2   4
                71.74         12.50        1.3155   10   1   0
                72.07          3.79        1.3103    8   3   2
                72.38          1.43        1.3054    5   7   1
                73.18          2.22        1.2931    0  10   2
                73.49          1.94        1.2884    8   4   1
                74.36         12.11        1.2754    5   0   5
                74.15          2.32        1.2786    2   8   3
                73.96          4.48        1.2814    9   3   0
                75.27          2.92        1.2622    5   4   4
                76.49          1.16        1.2452    7   5   2
                76.79          4.95        1.2411    0  11   1
                77.44          1.15        1.2323    4   7   3
                77.58          1.73        1.2304    4   8   2
                77.88          1.25        1.2264    2  10   1
                78.73          3.46        1.2152    3   4   5
                80.16          1.67        1.1971    0   0   6
                80.89          1.81        1.1881    6   1   5
                80.71          1.03        1.1903    4   6   4
                81.12          3.93        1.1853   11   1   1
                83.38          1.64        1.1588    3   0   6
                83.90          6.84        1.1530   10   1   3
                85.10          1.10        1.1397    1  11   2
                86.05          1.04        1.1295    6   5   4
                86.03          2.04        1.1297    9   3   3
                87.64          1.00        1.1131    1   4   6
                89.24          2.27        1.0972   10   0   4
                89.76          1.87        1.0922    3   3   6
                89.76          1.87        1.0922    3   3   6
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.