The smoothing of the surface of the carving with a series of progressively finer abrasives to achieve a range of finishes. There are different gradations of polish, ranging from a basic matt one to an extremely high gloss finish. A matt one can be achieved by rubbing emery, sandstone or pumice over the surface of the stone, usually with water to help lubricate the process. Finer levels of polish can then be achieved by using finer substances, like sand and burnt and crushed animal bones mixed with water into a paste. Matt polishes are common on high-quality Roman sculpture and high gloss finishes are also found, though these are rarer on ancient than Baroque and modern sculpture. Only certain stones can take a polish, among them marble, various hard granites and porphyries, and certain types of limestone.