Thermally stable ceramic media for use in high temperature environments

A chemical processing apparatus comprising a plurality of ceramic media formed at a sintering temperature, said media arc physically distinct and readily separable from one another after thermal cycling in the apparatus from a first temperature that is less than the media's sintering temperature to a second temperature which is at least 50° C. higher than the media's sintering temperature and then back to the first temperature, wherein said media comprises MgO, SiO2 and Al2O3, said MgO is between 48 and 78 percent by weight, said SiO2 is between 5 and 30 percent by weight and said Al2O3 is between 5 and 30 percent by weight of said media and wherein said media's porosity is between 24 percent and 38 percent based on media's apparent volume.