MICROSTRUCTURE OF FLINT AND OTHER CHERT RAW MATERIALS*

The crystallite size, microstrain, stacking disorder and moganite content of flint and other chert raw materials were studied by X‐ray powder diffraction profile analysis. The broadening of the X‐ray reflections of all microfibrous quartz varieties is due to both anisotropic small crystallite size and anisotropic microstrain. The microstructure varies for samples of different origin. The moganite content and the number of structural defects are higher in flint than in older chert and petrified wood. The X‐ray diffraction pattern of the cortex of flint differs from that of the core material, whereas those of the patina and the unweathered interior of the rocks do not.