gems, diamond, Russia, Ural Mountains

This thesis has investigated the geological origin of diamonds from the Ural Mountains. A set of inclusion-bearing diamonds from alluvial deposits in the western part of the Urals was characterised on the basis of their morphological features, nitrogen contents and nitrogen aggregation states, carbon and nitrogen stable isotopes, mineral inclusion geochemistry and radiometric isotopic ages of the inclusions. The vast majority of the studied diamonds are rounded dodecahedra, which indicates that the diamond population has experienced major resorption after crystallisation. The majority of the diamonds are affected by radiation damage and display evidence of transportation. Non-abraded diamonds exhibit similar surface features to those abraded, so they are probably of similar origin. The studied inclusion-bearing set of diamonds shares some characteristics with the overall, mostly inclusion-free, diamond population from the Ural Mountains. This similarity in physical characteristics strongly suggests that the Ural diamonds are all part of a single population.