Results of experimental studies of the synthesis glass ceramics of the MgO–SiO2 system by plasma melting at atmospheric pressure are presented. According to electron microscopy data, during melt crystallization rate of 287 ± 5 K/s, the surface morphology is represented by dense packing of rhombic dodecahedral Mg2SiO4 crystals (there is no open porosity). In this case, the matrix is ​​characterized by the formation of dense framework with clear linear arrangement of spherical inclusions corresponding to the MgSiO3 phase. Result of synthesis by plasma melting, glass ceramics with density of 3.56 g/cm3 and microhardness of up to 15 GPa were obtained. It is assumed that glass-ceramics with such a composition can be considered as an excellent option for the development of economical high-quality refractory.