Preliminary studies on the formation of the carbonaceous mesophase from a petroleum-derived asphalt by Conoco was carried out through solvent fractionation. The pentane solubles fraction produced a mesophase with a texture of medium-grained mosaics, while the asphaltene fraction yielded fine-grained mosaic structures, but gave a much higher carbonization yield. Further separation of the pentane solubles was achieved through elution with the following solvents of increasing polarity: (1) hexane, (2) toluene, (3) toluene/ methanol (4:1), (4) toluenelmethanol (2:1) (5) methanol. It was found that the toluene fraction gave the best mesophase with a coarser grained mosaic texture than even that of the pentane solubles fraction from which it was derived. The results were explained in terms of the plasticity of the system, which differed depending on the nature of the precursor molecules present in the various fractions.