The nucleation and growth of diamond crystals on single crystal copper surfaces has been studied. Microwave plasma enhanced chemical vapor deposition (MPECVD) was used for diamond nucleation and growth. Prior to diamond nucleation, the single crystal copper surface is modified by carbon ion implantation at an elevated temperature (∊820 °C). This procedure leads to the formation of a graphite film on the copper surface, resulting in an enhancement of diamond crystallite nucleation. A simple lattice model has been constructed to describe the mechanism of diamond nucleation on graphite as 〈111〉diamond parallel to 〈0001〉graphite and 〈110〉diamond parallel to 〈11$\overline 1$0〉graphite. This leads to a good understanding of diamond growth on carbon-implanted copper surfaces.