Peculiarities of nitrogen impurity aggregation in diamonds from the Sytykanskaya pipe, Yakutia

This paper presents the photoluminescence and EPR experiments performed on two varieties of diamond crystals from the Sytykanskaya pipe: small crystals which were inclusions in the ancient olivines, and large sized specimens. Small crystals and the cores of large crystals contain B and P2 nitrogen defects whereas the outer zone of large diamonds includes A nitrogen centers and their derivatives with vacancies. Coatings of large diamonds are a product of a second step of crystallization. The interpretation of data obtained proposes that small crystals from Sytykanskaya pipe are the most ancient of the Yakutia province, and that the generation of the P2 centers is a result of B centers destruction during early plastic deformation.