Polycrystalline diamond films were deposited on molybdenum substrates in an atmospheric-pressure radio-frequency induction plasma. The plasma consisted of argon into which hydrogen and methane were coaxially injected. The hydrogen-methane jet impinged in stagnation-point flow upon a water-cooled substrate located downstream of the induction coils. A series of eight experiments investigated the effect of five operating parameters. Deposited films were characterized by scanning electron microscopy, Raman spectroscopy, and x-ray diffraction. Each set of parameters was found to yield a particular crystal morphology with good reproducibility. The major correlation found was for the effect of the methane-hydrogen ratio. Regardless of the value of other parameters, well-faceted crystals were always obtained when the ratio equalled 1%, whereas cauliflower or ball-like structures were always obtained with a 5% methane-hydrogen ratio.