Otavite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050677
      Graf D L
      American Mineralogist 46 (1961) 1283-1316
      Crystallographic tables for the rhombohedral carbonates

      CELL PARAMETERS:   4.913837   4.913837   16.32577   90.00000   90.00000   120.0000
      SPACE GROUP: R-3c
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                23.59         73.73        3.7735    0   1   2
                30.35        100.00        2.9456    1   0   4
                32.92          3.70        2.7210    0   0   6
                36.57         33.82        2.4569    1   1   0
                40.27          5.18        2.2393    1   1   3
                43.97         24.19        2.0590    2   0   2
                48.22         14.93        1.8868    0   2   4
                49.53         21.12        1.8401    0   1   8
                50.01         32.59        1.8235    1   1   6
                58.46         17.65        1.5781    1   2   2
                60.74          4.92        1.5243    1   0  10
                61.99         13.11        1.4964    2   1   4
                63.10          5.95        1.4728    2   0   8
                65.81          8.49        1.4185    3   0   0
                69.00          3.06        1.3605    0   0  12
                73.01          4.05        1.2952    0   2  10
                75.18          6.75        1.2632    1   2   8
                75.56          2.04        1.2578    3   0   6
                75.56          2.04        1.2578    0   3   6
                80.69          5.07        1.1902    1   1  12
                82.54          1.13        1.1681    3   1   2
                84.52          4.88        1.1458    2   1  10
                85.62          2.19        1.1338    1   3   4
                86.49          1.57        1.1247    0   1  14
                86.97          1.56        1.1196    2   2   6
                86.97          1.56        1.1196    2   2   6
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.