Low-Nitrogen Diamond Growth in the Fe–C–S System

The first results on diamond growth in the Fe–С–S system with 1 wt % S (relative to Fe) at 6 GPa and 1450°C have been reported. The diamonds obtained contain about 30 ppm N, on average, and belong to the low-N transition diamond group Ib–IIa. It has been suggested that the reduction conditions formed by certain active elements such as S can play an important role in the formation of natural low-N diamonds.