The features of crystallization of cristobalite in quartz glass obtained on plasma torches of JSC "Dinur", the raw material for melting of which is quartz sand of the Ramenskoye mining and Processing Plant, are considered. On the high-temperature dilatometer DIL-402 of the company “Netzsch" (Germany), dependences of changes in the linear dimensions of quartz glass samples in various heating–cooling modes were obtained. The service process of refractory quartz ceramics made of opaque quartz glass is modeled.