An X-ray topographic study of impurity platelet distribution and size in an inhomogeneous diamond

A natural diamond was shown by x-ray topography to consist of an included diamond exhibiting strong evidence of slip on {111} planes which was surrounded by a parallel overgrowth in which only local and weak signs of slip were seen. A topographic study of intensities of the anomalous diffuse ‘spike’ reflections demonstrated that the inclusion was relatively poor in nitrogen impurity platelet precipitates compared with the overgrowth. It way shown how platelet diameters could be measured from the sharpness of ‘spike’ topograph images, and an application of the technique indicated that platelet diameters in the outermost parts of the diamond were in the range 150 to 200 Å. Sequences of depth, temperature and stress conditions which could have been responsible for the observed structure of the diamond are discussed.