In this work, asphaltenes were obtained from five different sources. Asphaltene yields of products from crude oil, asphaltite, oil shale, tar sand and bituminous coal were 7.5%. 13.6% , 8.4%, 5.0% and 7.8%, respectively. Asphaltenes and resins are two of the several, but important, heavy organics present in petroleum fluids. Asphaltenes are operationally defined as the non-colatile and polar fraction of petroleum that is insoluble in n-alkanes (i.e. n-pentane). Conversely, resins are defined as the non-colatile and polar fraction of petroleum that is soluble in n-alkanes (i.e. n-pentane) and aromatic solvents (i.e. toluene) and insoluble in ethyl acetate. (C) 2002 Elsevier Science Ltd. All rights reserved.