A thick, homoepitaxial diamond film was deposited on the microcracked (100) tip of a brilliant cut type Ia natural diamond anvil by microwave plasma-assisted chemical vapor deposition (MPCVD). The rapid (up to 20 μm/h), highly anisotropic growth resulted in a modification of the original geometry of the central flat and culet regions. The size of the diamond culet grew from 350 to ∼800 μm in diameter in about 8 h. The deposited film was characterized by optical microscopy, micro-Raman and photoluminescence (PL) spectroscopy. Raman analysis of the deposit confirms that its crystalline quality is comparable to that of the substrate, and that it contains no amorphous or graphitic phases of carbon. The epitaxial overlayer exhibits two prominent PL bands not observed from the substrate with zero-phonon (ZPL) lines at 1.945 and 2.156 eV, which are attributed to nitrogen-related defect complexes. The present work shows the potential viability of high growth rate homoepitaxy by MPCVD for numerous industrial and scientific applications, such as high pressure research.© 1995 American Institute of Physics.