Hydrothermal growth of diamond particles and films was achieved during interaction of a liquid organic precursor (C2H3Cl3) and 10 M NaOH in the presence of diamond or cubic BN seeds at the temperature 300 degrees C and 1 GPa pressure. Synthesized diamond was thoroughly characterized by TG-DTA, SEM, EDX, TEM, Raman spectroscopy and had (220) preferable orientation according to XRD pattern in the case of the film.