Texture and Structure Features of Yakutites from Placers of the Anabar Diamondiferous Region

Abstract

This paper reports new study data on structural features of polycrystalline diamonds (yakutites) from placers of the Anabar diamondiferous region obtained by X-ray and optical spectroscopy. All studied samples are fine-grained (up to 1 μm) polycrystals. The diffractograms of most samples show reflexes related to lonsdaleite defects in the diamond structure. Yakutites are inhomogeneous: diffractograms of different parts of diamond aggregates show different reflections of texture and micrograins with a monocrystalline structure. A “bell” in the single-phonon region of IR spectra indicates defects in the crystal structure of yakutites and a significant structural stress. An aggregated nitrogen line is absent in the photoluminescence spectra of yakutites, likely due to the fact that they were ejected outside the crater after the solid-phase synthesis stage and were relatively rapidly cooled down.