Origin identification of rough diamonds using impurity composition from polished diamonds

Among the typomorphic features of rough diamonds, only the defect-impurity composition is preserved after their processing into jewelry diamonds. In this study, 60 samples from three different deposits of the Yakutian diamond province were examined. The concentrations of H-, B2-, N3-, P1-, 490.7-, N3V-centers in the original rough diamonds and in the polished diamonds derived from them were determined using IR, UVVis, and EPR spectroscopy. Correlation-regression analysis of the obtained data revealed correlation between the concentrations of impurity defects in the original rough diamond crystals and in the resulting jewelry diamonds, indicating an “inheritance” of the defectimpurity composition from the rough to the polished diamonds. Based on the experimental data, linear regression models were derived to describe the dependence of defect concentrations in polished diamonds on their concentration in rough diamonds from the specified deposits. However, because the formation conditions of diamonds from different deposits can be similar, it is not possible to determine the geographic origin of the original diamond from the impurity-defect composition of a single polished diamond. The results indicate that, assuming the diamonds originate from the same deposit, a statistically significant sample for determining their source deposit consists of 400 polished diamonds.