Coherent growth of α-Si3N4 precipitates is observed in a silicon matrix after implantation of 150 keV N+ at a dose of 1×1018/cm2 into (110) silicon. The near-channeling conditions lead to a band of discrete precipitates, 0.5 μm below the continuous, polycrystalline buried nitride layer. No misfit dislocations or strain contrast were observed in the silicon matrix despite a 10% lattice mismatch along the Si3 N4 [0001] direction and a 1% mismatch along directions perpendicular to [0001]. The mismatch appears to be accommodated entirely within the precipitate by a mosaic structure consisting of single-crystal subunits, coherent with Si at the Si3 N4 (0001)/Si{111} interface, but incoherent perpendicular to these planes.