In order to study the nature and extent of structural disorders in kaolinite, a sample from Singhbhum, India, has been subjected to x-ray diffraction and electron-microscope examination. Electron-microscope studies revealed the distribution of particle sizes. X-ray diffraction line profiles of different reflections were corrected for geometrical factors by the Stokes deconvolution method. Line broadening and Fourier analysis methods revealed that the particles were flaky with less extension in the c direction than in the a and b directions. The average particle has been shown to have a length and breadth of 700 Å and a thickness of 219 Å. Expressions for apparent particle size and particle-size line profile for triclinic crystals with parallelepiped form have been worked out. With the help of these expressions, the pure diffraction line profiles were corrected for particle-size effects and pure-defect line profiles were obtained. Fourier analysis of these line profiles showed that the probability of a layer shift by an amount ⅓ b or ⅔ b occuring was .046. From the integral width and peak shift in the pure-defect line profiles of 00 l reflections, the fractional extent and probability of interlayer variation has been found to be .126 and .057 respectively. A possible interpretation of interlayer-distance change in metakaolin has been put forward on the basis of these data.