TIPOMORFNY FEATURES OF QUARTZ
Calculation data are herein described for coherent-scattering region sizes and micro-distortion values by the approximation method for quartz samples of different genesis. Comparison of two methods for micro-structure analysis is presented: rapid test method for half-width profiles approximated by the Cauchy or Gauss, Voigt functions, and diffraction line shape analysis taking into account the asymmetry of instrumental distortions and physical profile. The researches were carried out on samples of chalcedony, Volga agate, jasper, brown quartz, quartz sand, sandstone rock quartz of core container rocks which were selected in the Samara Region with indication of their detailed location. Also gangue quartz was used as a reference. The choice of analytical lines for the mineral to be investigated and the reference was grounded. The rapid X-ray diffraction method to determine quartz micro-structure parameters at approximation by the Voigt function was tested taking into account the limitations in the instrument operation conditions with the set rapidness and accuracy. The obtained data were compared: the coherent-scattering regions and the crystallinity index from the studied quartz samples. Advantages and disadvantages of the rapid test method for half-width profiles approximated by the Cauchy or Gauss, Voigt functions, and diffraction line profile shape analysis taking into account the asymmetry of instrumental distortions and physical profile. The obtained micro-structure parameters: the coherent-scattering region sizes and the quartz micro-distortion value may be given as an additional characteristic in determining the particle size distribution of terrigenous rocks. Using structural typomorphic features, it is possible to differentiate similar quartz sandstones.