A model, so-called heterogeneous two-dimensional (2D) nucleation model, is presented to describe the effect of foreign particles on the growth and surface instability of growing crystals. The occurrence of foreign bodies on growing surfaces of crystals will serve as precursors for heterogeneous 2D nucleation, so that it will promote rapid growth at relatively low supersaturations at the regions where the foreign particles are in contact with the crystal surface. At high supersaturations, due to the limitation of effective transport, heterogeneous 2D nucleation will become kinetically unfavourable. Then, foreign particles have less or no effect on crystal growth. To check the model, the theoretical results are confronted with experimental ones. A novel phenomenon of a needlelike pattern of surface instability caused by solid particle induced growth was observed for the first time for naphthalene crystals grown from the melt. This particulate-induced surface instability occurs in a completely different regime of G/V compared to the dendriticlike surface instability, which turns out to be in excellent agreement with our prediction.