ETCHING OF DIAMOND CRYSTALS IN A DRY SILICATE MELT AT HIGH P-T PARAMETERS

Abstract

A series of experiments was carried out on the etching of diamond crystals of an octahedral habit in low-temperature alkali basalt melt at 3.0 GPa and 1300 degreesC. Crystal morphologies similar to those of natural diamonds were observed. The composition of experimental fluid was determined by chromatographic analysis. Three types of diamond morphogenesis due to etching processes were distinguished. They are controlled by the fluid regime of the system. It was shown that the rate of diamond crystal dissolution increased with increasing H2O content.