Cristobal it izat ion of quartz is a perspective method for a preparation of a raw material for melting especially pure quartz glass. For the control of a degree of cristobalitization X-ray diffraction and IR-spectroscopy were used. The degree of cristobalitization has been estimated for heat-treated quartz powders from Kyshtimskoe and Kyznechihinskoe deposits. It is shown, that the results received by these methods correlate well with each other.