Spectroscopic and Morphological Characteristics of Diamonds from the Grib Kimberlite Pipe

摘要

Investigations of diamonds from a new diamondi-ferous province discovered in 1980 in the Arkhangelsk district of Russia are of great interest. It was established that the Arkhangelsk diamond differs from its Yakutian counterpart by an extremely high content of round rhombododecahedra and tetrahexahedra and cubic crystals. The increased contents of round rhombododecahedra and tetrahexahedra with characteristic "edged suture" and octahedral-rhombododecahedral crystals, which are characterized by sheaflike hatching, block structure, and drop-shaped sculpture, indicate more intense epigenetic dissolution of diamonds in the majority of kimberlites of the Arkhangelsk province relative to those in Yakutia. However, diamonds from the Grib kimberlite pipe discovered in 1996 differ from those from other kimberlite pipes of the Arkhangelsk district. They are characterized by nearly equal contents of octahedra and rhombododecahedra, low contents of tetrahexahedra and cubes, and wider abundance of plastically deformed crystals. It is interesting in this context to carry out a comparative study of paramagnetic centers in diamonds from the Grib kimberlite pipe and other pipes of the Arkhangelsk dia-mondiferous province. Paramagnetic centers in diamonds from the earlier discovered Lomonosovskaya, Pionerskaya, and Pomorskaya pipes were studied with EPR spectroscopy in our previous work.