A new method for growth of diamond seed crystals at metastable conditions is described. The process is realized isothermally (at temperatures in the range of 1000 K to 1400 K) in the closed volume of a quartz ampoule, via appropriate chemical transport reactions or in a CVD-apparatus. Vitreous carbon materials and other non-equilibrium forms of carbon, representing state of frozen-in disorder, increased thermodynamic potential and chemical affinity, are used as a constant driving force of isothermal crystallization.The experiments are based on the detailed analysis of the thermodynamic properties of carbon modifications and on the influence of dispersity and the degree of disorder on their thermodynamic potential. Additional kinetic factors, influencing the diamond growth, like introduction of active substrates and mechanism of incorporation of carbon atoms in growing diamond face are also analyzed discussed in their possible technical application. (C) 2003 Kluwer Academic Publishers.