Combining results from small-angle X-ray scattering, small-angle neutron scattering, and shear rheology studies we find that the average unsolvated asphaltenic colloidal particle in Ratawi vacuum residue has an apparent molecular weight of approximately 100 000 amu and volume of approximately 150 000 angstrom3. The asphaltenic colloidal particles are solvated by the maltenes in vacuum residue. The average solvated particles has an apparent molecular weight of approximately approximately 300 000 amu and volume of approximately 450 000 angstrom3.