Cordierite monoliths with surface area up to 255 m(2)/g have been obtained by acid treatment with a variety of inorganic and organic acids. This value is more than 500 times higher than the surface area of the original cordierite. The treated cordierite has been studied by BET and BJH surface area measurements, X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), and scanning electron microscopy (SEM). The high surface area is due to the removal of Al and Mg ions from the silicate structure and subsequent generation of free amorphous silica on the surface of the cordierite. Evolution of the pore structure was followed as a function of acid type and processing conditions. The data indicate that monoliths with well-controlled pore size distributions can be produced. As such, the treated monoliths have potential for use as catalyst supports, especially in cases where high-surface-area washcoats are undesired or impractical. The treated monoliths retain surface areas in excess of 20 m(2)/g up to 900 degrees C, and can be further stabilized by the application of a thermally stable washcoat.