Calcite
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R050307
      Graf D L
      American Mineralogist 46 (1961) 1283-1316
      Crystallographic tables for the rhombohedral carbonates

      CELL PARAMETERS:   4.990000   4.990000   17.06150   90.00000   90.00000   120.0000
      SPACE GROUP: R-3c
      X-RAY WAVELENGTH:     1.541838
               2-THETA      INTENSITY    D-SPACING   H   K   L
                23.08          8.10        3.8525    0   1   2
                29.43        100.00        3.0339    1   0   4
                31.47          2.43        2.8421    0   0   6
                36.01         13.71        2.4933    1   1   0
                39.45         20.16        2.2833    1   1   3
                43.20         14.26        2.0932    2   0   2
                47.16          6.16        1.9263    0   2   4
                47.55         19.67        1.9114    0   1   8
                48.55         20.02        1.8743    1   1   6
                56.61          3.73        1.6248    2   1   1
                57.45          9.18        1.6031    1   2   2
                60.72          5.28        1.5243    2   1   4
                61.05          2.41        1.5169    2   0   8
                61.43          3.18        1.5085    1   1   9
                63.11          2.29        1.4723    1   2   5
                64.72          6.84        1.4395    3   0   0
                65.66          3.91        1.4210    0   0  12
                69.25          1.51        1.3560    2   1   7
                70.30          2.13        1.3382    0   2  10
                72.95          2.69        1.2959    1   2   8
                77.22          1.93        1.2346    1   1  12
                81.59          2.24        1.1791    2   1  10
                83.84          1.57        1.1531    1   3   4
                83.84          1.57        1.1531    1   3   4
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.