An X-ray topographic study of planar growth defects in a natural diamond

This is the authors' abstract. We don't add key points for this paper.

Ten outcropping planar defects 30 to 70 μm in edge length lying in {111} planes inclined to the octahedral faces of an unusually perfect diamond (diameter 4 mm) were revealed by diffraction contrast but could not be detected optically. Those defects in the form of an equilateral triangle with one edge in the crystal surface show stacking-fault-type fringes and are bounded by Frank sessile dislocations. A single regular tetrahedral fault surface lying wholly within the crystal produces a type of x-ray interference not previously observed. Its diffraction theory is outlined, and computed fringe positions and spacings agree well with observation.