DIAMOND INTERACTION WITH SILICATE MELTS IN A HYDROGEN ATMOSPHERE

Abstract

Diamond crystals from different bedrock sources have specific typomorphic features, which are controlled by the conditions of growth (physical and structural characteristics, trace element composition, etc.) and postgrowth transformations. The latter are most distinctly expressed in changes in crystal morphology (dissolution patterns). The relation of certain macro- and micromorphological features of crystals to dissolution can be convincingly supported by the experimental reproduction of their analogues. The genesis of rounded diamonds was hotly debated until they were produced by high-pressure etching of initially flat-faced crystals in silicate melt in the presence of water–carbon dioxide fluid. At present, an important problem is not only the simulation of natural forms and sculptures on diamond crystals during etching but also the determination of the boundary physicochemical conditions of their appearance.