Self-adhesive carbonaceous grains for use in the production of high density carbon artifacts and high performance carbon-carbon composites are made by processes such as oxidation and heat treatment of specific mesophase pitches. The present carbonaceous grains exhibit excellent binding properties, shape stability when molded, and high density with higher carbonization yield, providing very high strength artifacts when their properties fall within the specific range of properties defined by their H/C and O/C values. High density carbon artifacts can be easily obtained by molding the grains and carbonizing or graphitizing the same.