Nitrogen-14 in Natural Diamonds

Abstract

Kaiser and Bond¹ showed, by mass-spectrographic analysis, that many type I diamonds contain up to 0.2 per cent of nitrogen-14 as impurity, and quantitatively correlated this fact with certain features of the type I infra-red and ultra-violet spectra. Smith et al.² also found by electro-spin resonance measurements that there is a C—N bond in about one half of the diamonds examined. A correlation has now been established between spike intensity and ultra-violet transparency in natural diamonds³, and dislocation loops and segregated platelets, presumed to be nitrogen, have been observed in etched diamonds by transmission electron microscopy⁴. Kaiser and Bond deduced that the nitrogen is substitutional and not interstitial, on the basis of density measurements on eight diamonds of gem quality.