Diamond crystallites were nucleated and grown from the vapor phase on silicon substrates previously processed into arrays of nanometer‐scale silicon wires. We found that the nanowires did not aid nucleation, and that the nucleation density on the nanowire base was very low (<104cm−2). Most importantly, we discovered that single diamond crystallites grew around the nanowires, infiltrating the nanowire arrays, forming new composite structures. This discovery clearly shows how inclusions can be trapped in vapor grown diamond crystallites, and challenges the common assumption that growth precursors on the diamond surface are relatively immobile. ©1995 American Institute of Physics.