In situ optical and birefringence measurements were applied in observing the crystallisation of very thin (greater than or equal to 1.1 mu m) n-paraffin crystals. Next, homologue impurities were found to reduce the crystal thickness even further to approximately 0.4 mu m. As such thin crystals are very sensitive to adsorption of (sub-) micron particles (e.g. dust particles) a new type of growth, i.e. ''particle-induced rough growth'', is induced. This growth is akin to the growth of steps in the presence of immobile impurities adsorbed on the surface. The measured mean distance between the obstructing (sub-) micron particles (12 mu m) is used to calculate the surface energy (36 mJ/m(2)) of the top and bottom faces of the n-paraffin crystals. And it was shown that this is a reasonable value for the surface energy of {001} faces of n-paraffin crystals. Further, it was shown that at fixed concentrations the saturation temperatures for thin crystals are different from those for thick crystals. These results can be explained in terms of a Gibbs-Thomson effect.