Quartz
      Diffraction data computed using the structure from the paper listed below, 
      along with the cell parameters refined from single crystal data of R100134
      Antao S M, Hassan I, Wang J, Lee P L, Toby B H
      The Canadian Mineralogist 46 (2008) 1501-1509
      State-of-the-art high-resolution powder x-ray diffraction (HRPXRD) illustrated
      with Rietveld structure refinement of quartz, sodalite, tremolite, and meionite
      Locality: not specified
      _database_code_amcsd 0006212

      CELL PARAMETERS:   4.9220  4.9220  5.4070   90.000   90.000  120.000
      SPACE GROUP: P3_221    

           ATOM        X         Y         Z     OCCUPANCY  ISO(B)
            Si     0.47000   0.00000   0.66667     1.000     0.490
            O      0.41460   0.26780   0.78543     1.000     0.861

            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:      35.23383208    
            The INTENSITY cut off value is   1.00

               2-THETA      INTENSITY    D-SPACING   H   K   L
                20.84         20.30        4.2626    1   0   0
                26.63         69.91        3.3475    0   1   1
                26.63         30.09        3.3475    1   0   1
                36.51          7.13        2.4610    1   1   0
                39.47          1.04        2.2830    0   1   2
                39.47          6.18        2.2830    1   0   2
                40.26          3.30        2.2399    1   1   1
                42.41          5.37        2.1313    2   0   0
                45.76          1.02        1.9828    0   2   1
                45.76          2.23        1.9828    2   0   1
                50.12         12.68        1.8199    1   1   2
                54.85          3.19        1.6737    0   2   2
                55.34          1.66        1.6600    0   1   3
                59.91          5.07        1.5440    1   2   1
                59.91          4.17        1.5440    2   1   1
                64.03          1.76        1.4541    1   1   3
                67.70          1.46        1.3840    2   1   2
                67.70          4.35        1.3840    1   2   2
                68.14          1.39        1.3762    0   2   3
                68.14          5.47        1.3762    2   0   3
                68.25          4.32        1.3742    0   3   1
                73.50          1.82        1.2885    1   0   4
                75.61          1.98        1.2577    3   0   2
                79.85          2.45        1.2012    2   1   3
                81.19          2.53        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.