Clarkeite
      Finch R J, Ewing R C
      American Mineralogist 82 (1997) 607-619
      Clarkeite: New chemical and structural data
      _database_code_amcsd 0001902

      CELL PARAMETERS:    3.9540   3.9540  17.6600   90.000   90.000  120.000
      SPACE GROUP: R-3m      
      X-RAY WAVELENGTH:     1.541838
      Cell Volume:    239.108
      Density (g/cm3):      6.770
      MAX. ABS. INTENSITY / VOLUME**2:      259.5321354    
      RIR:     12.482
      RIR based on corundum from Acta Crystallographica A38 (1982) 733-739
               2-THETA      INTENSITY    D-SPACING   H   K   L   Multiplicity
                15.05        100.00        5.8867    0   0   3         2
                26.51         71.65        3.3617    1   0   1         6
                27.95         88.61        3.1926    0   1   2         6
                30.37         26.00        2.9433    0   0   6         2
                33.11         35.16        2.7058    1   0   4         6
                36.55         20.60        2.4585    0   1   5         6
                44.61         12.63        2.0311    1   0   7         6
                45.90         36.32        1.9770    1   1   0         6
                46.27          7.79        1.9622    0   0   9         2
                48.58         30.86        1.8741    1   1   3        12
                49.10         23.50        1.8554    0   1   8         6
                53.79         10.47        1.7041    0   2   1         6
                54.60         13.82        1.6808    2   0   2         6
                56.04         27.21        1.6412    1   1   6        12
                57.76          8.05        1.5963    0   2   4         6
                58.83         11.01        1.5696    1   0  10         6
                60.05          5.50        1.5407    2   0   5         6
                63.18          3.12        1.4717    0   0  12         2
                64.06          7.39        1.4536    0   1  11         6
                65.94          4.34        1.4167    0   2   7         6
                67.22         14.53        1.3927    1   1   9        12
                69.48          7.90        1.3529    2   0   8         6
                73.35          8.50        1.2908    2   1   1        12
                74.03         11.05        1.2806    1   2   2        12
                75.25          2.53        1.2627    1   0  13         6
                76.74          7.39        1.2420    2   1   4        12
                77.68          4.85        1.2293    0   2  10         6
                78.75          5.45        1.2152    1   2   5        12
                81.28          4.20        1.1837    0   1  14         6
                81.54          9.00        1.1805    1   1  12        12
                82.34          3.68        1.1711    2   0  11         6
                84.05          4.83        1.1516    2   1   7        12
                84.97          5.39        1.1414    3   0   0         6
                86.94          3.03        1.1206    3   0   3         6
                86.94          3.03        1.1206    0   3   3         6
                87.34          8.58        1.1165    1   2   8        12
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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.