Svanbergite
Diffraction data computed using the structure from the paper listed below, 
along with the cell parameters refined from the powder pattern of R050549
      Kato T, Miura Y
      Mineralogical Journal 8 (1977) 419-430
      The crystal structure of jarosite and svanbergite
      Locality: Dover Andalusite Mine, Nevada, USA

      CELL PARAMETERS:   6.9880  6.9880 16.6050   90.000   90.000  120.000
      SPACE GROUP: R-3m      

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Sr     0.00000   0.00000   0.00000     1.000     1.290
            Al     0.16667  -0.16667  -0.16667     1.000     0.210
            P      0.00000   0.00000   0.30950     0.500     0.110
            S      0.00000   0.00000   0.30950     0.500     0.110
            O      0.00000   0.00000   0.39930     1.000     0.360
            O      0.21800  -0.21800  -0.05580     1.000     0.460
            OH     0.12470  -0.12470   0.13580     1.000     0.130

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    0.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  5 +/-  5 +/- 15
            MAX. ABS. INTENSITY / VOLUME**2:      26.73961228    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                15.58         50.23        5.6859    1   0   1
                16.01          3.05        5.5350    0   0   3
                18.14          3.17        4.8905    0   1   2
                25.49         42.35        3.4940    1   1   0
                26.03          3.39        3.4233    1   0   4
                30.02          7.44        2.9769    0   2   1
                30.25        100.00        2.9546    1   1   3
                31.47          5.90        2.8430    2   0   2
                32.35         10.78        2.7675    0   0   6
                36.75          8.42        2.4452    0   2   4
                39.78          3.91        2.2660    2   1   1
                40.32          6.06        2.2367    2   0   5
                40.86         34.30        2.2085    1   0   7
                40.92         15.96        2.2052    1   2   2
                41.63          5.08        2.1694    1   1   6
                44.94          1.56        2.0173    3   0   0
                45.26          5.23        2.0034    2   1   4
                48.00         31.14        1.8953    0   3   3
                48.00          2.43        1.8953    3   0   3
                48.31          2.03        1.8838    1   2   5
                52.37         22.84        1.7470    2   2   0
                53.54          2.64        1.7116    2   0   8
                54.99          1.03        1.6700    1   3   1
                55.83          3.60        1.6466    2   1   7
                56.40          4.33        1.6315    1   1   9
                56.45          1.14        1.6302    0   3   6
                56.45          1.26        1.6302    3   0   6
                57.56          1.84        1.6013    1   0  10
                61.95          5.51        1.4980    3   1   5
                62.39          4.08        1.4884    0   4   2
                62.91         10.38        1.4773    2   2   6
                63.95         16.22        1.4557    0   2  10
                65.69          3.56        1.4215    4   0   4
                67.73          2.37        1.3835    3   2   1
                68.48          4.41        1.3702    1   3   7
                68.98          4.01        1.3614    0   3   9
                70.02          1.29        1.3438    2   1  10
                71.43          3.86        1.3206    4   1   0
                73.76          4.02        1.2846    1   4   3
                73.76          6.57        1.2846    4   1   3
                76.17          1.97        1.2498    1   0  13
                80.09          8.09        1.1982    3   2   7
                81.55          4.15        1.1805    1   3  10
                82.89          1.46        1.1647    3   3   0
                85.00          1.77        1.1411    3   0  12
                87.16          2.85        1.1183    4   0  10
                87.46          4.80        1.1152    2   1  13
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.