Quartz
Diffraction data computed using the structure from the paper listed below,
along with the cell parameters refined from the powder pattern for R110104
      Levien L, Prewitt C T, Weidner D J
      American Mineralogist 65 (1980) 920-930
      Structure and elastic properties of quartz at pressure
      P = 1 atm
      _database_code_amcsd 0000789

      CELL PARAMETERS:   4.9170  4.9170  5.4090   90.000   90.000  120.000
      ALTERNATE SETTING FOR SPACE GROUP: P3_221    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Si     0.46970   0.00000   0.00000     1.000     0.617
            O      0.41350   0.26690   0.11910     1.000     1.059

            X-RAY WAVELENGTH:     1.541838
            BOUNDS ON TWO THETA:    5.0  90.0
            LIMITS IMPOSED ON THE INDICES ARE:  +/-  3 +/-  3 +/-  4
            MAX. ABS. INTENSITY / VOLUME**2:      35.13309713    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                20.86         19.91        4.2582    1   0   0
                26.64         69.90        3.3458    0   1   1
                26.64         30.10        3.3458    1   0   1
                36.55          7.13        2.4585    1   1   0
                39.47          1.01        2.2830    0   1   2
                39.47          6.19        2.2830    1   0   2
                40.30          3.19        2.2382    1   1   1
                42.46          5.24        2.1291    2   0   0
                45.80          1.00        1.9812    0   2   1
                45.80          2.09        1.9812    2   0   1
                50.15         12.59        1.8192    1   1   2
                54.88          3.09        1.6729    0   2   2
                55.33          1.61        1.6603    0   1   3
                59.97          4.11        1.5426    2   1   1
                59.97          4.93        1.5426    1   2   1
                64.04          1.72        1.4539    1   1   3
                67.75          4.18        1.3831    1   2   2
                67.75          1.38        1.3831    2   1   2
                68.15          1.36        1.3759    0   2   3
                68.15          5.32        1.3759    2   0   3
                68.32          4.13        1.3729    0   3   1
                73.48          1.73        1.2888    1   0   4
                75.67          1.91        1.2568    3   0   2
                79.89          2.30        1.2007    2   1   3
                81.18          2.41        1.1848    1   1   4
================================================================================
       XPOW Copyright 1993 Bob Downs, Ranjini Swaminathan and Kurt Bartelmehs
  For reference, see Downs et al. (1993) American Mineralogist 78, 1104-1107.