Scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectrometry has been used to characterize Athabasca oil sand (AOS) and various coked residues prepared therefrom for mineral phase and size distribution. The composite mineral particles were classified into ten particle size ranges. Increasing coking time caused an increase in the percentage of small particles of quartz and clay The AOS is relatively rich in sulfur and iron; 6.17% and 0.173%, respectively. The micrographs of AOS show that the majority of the sand grains are not in direct contact with each other and that the bitumen forms a thin layer between the grains. For the coked residues, the sand grains were connected to one another by their coke bridges.