HYDROCARBON INCLUSIONS IN SYNTHETIC DIAMONDS

Primary (syn-growth) fluid inclusions in synthetic diamonds, produced within the field of their thermodynamic stability in a high-pressure s plit-sphere apparatus using the temperature gradient method, have been studied by optical microscopy and Raman spectroscopy. Inclusions in t abular diamond crystals contain CH4 + other higher molecular hydrocarb ons, whereas inclusions in octahedral and dodecahedral diamonds contai n only CH4. All inclusions in octahedral and dodecahedral diamonds con tain graphite, which covers the walls of vacuoles as an opaque film. T he formation of this film is most likely associated with precipitation of carbon from fluid on cooling. The obtained results emphasize the p ossible role of hydrocarbons in the process of diamond crystallization .