A pellet made from a mixture of natural occurring clays comprising porcelain clay, earthenware clay, and kaolin clay. In some embodiment, the pellet has an alumina content between about 5.5% and about 35%, an apparent specific gravity from about 2.10 to about 2.55 g/cc, and a bulk density of from about 1.30 to about 1.50 g/cc. The pellet is useful in hydraulic fracturing of oil and gas wells, and has greater conductivity than sand at pressures up to 8,000 psi as measured by Stim-Lab after 50 hours and 275° F. on Ohio Sandstone, in the presence of deoxygenated aqueous 2% solution of KCI.