Home – Home – Jornals – Russian Geology and Geophysics 2006 number 2

Exemplified by one of the diamond deposits (Guaniamo, Venezuela), it has been shown that the complex study of the internal structure of diamond crystals by the Laue-SR method yields new information on diamond formation in deep-seated zones of continental lithosphere. The diamonds initially grown as sufficiently large crystals underwent several stages in their postgrowth history, owing to changes in both pressure and temperature and to mechanical actions. In their ultimate state, the crystals are flat cleavage platelets, slightly dissolved (or etched), or chips of other configurations with obvious traces and figures of plastic deformation. The weakening of brown color usually observed in deformed but nonannealed diamond crystals and typical traces of polygonization revealed by the Laue-SR method suggest long-lasting annealing, which occurred after the chips subparallel to sliding plane {111} had been separated from the crystals. The applied technique is useful to study diamond crystals in situ and to obtain additional genetic information.