Nanodiamond formation in natural processes from fluid systems at low P-T parameters

The paper presents a new physicochemical model of the formation of nanosized diamonds from an OHC fluid system under low temperature and pressure conditions corresponding to the graphite stability area. This model in general explains the specific features of the composition of gas mixtures for CVD and hydrothermal synthesis in terms of diamond growth and formation under metastable conditions. It also explains the origin of nanodiamonds and microdiamonds in metamorphic rocks of the Earth's crust and the genesis of nanodiamonds in outer space at low temperatures and pressures.