The steatite ceramics are mostly used in electrotechnics. Although distinguished by their mechanical and electrical properties they are unstable. The desirable, high temperature protoenstatite phase inverses into magnesium metasilicate low-temperature form—clinoenstatite, even upon standing. In this work the steatite polymorphism was studied in relation with steatite mechanical properties and microstructure. It was find out that the stabilization of protoenstatite in steatite body is achievable by the development of small crystals, yet it is still not resistant to action of water what put in question its potential application as dental material.