When a powder mixture of diamond and silicon is heated by microwaves, heteroepitaxial growth of SiC is observed on the (111) as well as on the (100) faces of the diamond. The SiC over-layer was characterized by X-ray diffraction and scanning electron microscopy. High-resolution scanning electron microscopy shows the presence of triangular silicon carbide on the (111) faces of diamond while prismatic crystals are found on the (100) faces. The crystal growth seems to be favored in the plane parallel to the face (111). (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.