Single crystalline diamond particles were grown on the ends of sharp silicon tips. The typical form of the particles was cubooctahedron with a (111) plane on the top. Field emission experiments of Si emitters with single crystalline diamond coating demonstrated hysteresis and normal emission modes. In the hysteresis mode, emission saturated at about 2 mu A. Fowler-Nordheim plots for data points below the saturation limit were nonlinear. Transformation from hysteresis to normal behavior occurred with increasing voltage. A modified model-of emission through dielectric layers was proposed for explanation of emission properties of diamond.