Quantitative electron energy-loss spectroscopy microanalysis of platelet and voidite defects in natural diamond

Abstract

Chemical analysis of ‘voidites’ in diamond reveals only nitrogen, whereas similar analysis of ‘platelets’ shows no detectable nitrogen. The method of analysis is electron energy-loss spectroscopy in a dedicated scanning transmission electron microscope. The voidite size ranges from 2 to 5 nm. The results suggest that the voidites arise from discontinuous precipitation of nitrogen on dislocations including dislocations bounding the platelets. The nitrogen in the voidites is very dense (one-half the atomic density of the diamond) and it seems probable that the diamonds are formed somewhat deeper in the Earth's mantle than previously estimated. © 1989 Taylor & Francis Group, LLC.