Onyx Professional Double-Sided 100% Siliglass Pumice Stone will smooth away calluses and dry patches faster than ever! Onyx takes pride in having the worlds best pumice stone! Sourced from Spain and made of 100% Siliglass this exfoliating stone is the best dry skin remedy around. There are two amazing sides to this pumice stones story. Side one is coarse green porous material that works as an exfoliator and callus remover. Side two is the fine smooth white material that works as a sander that buffs all impurities away revealing soft and supple skin.