Abstract: A method of making glass-silicate tiles includes pouring an input raw material containing glass granulate into a heat-proof mold, wetting the input raw material and making an initial blank thereby, heat treating of the blank by gradual heating and by gradual cooling by stages with holding period between the stages wherein a first heating stage is performed predominantly by heating a bottom side of the blank with higher speed of heating of a lowering layer than of an upper layer of the blank to accelerate gases to release the blank through the upper layer up to reach of the temperature of beginning of glass granulate sintering (T.sub.f) in the lower layer, and the temperature not exceeding a glass granulate transformation temperature (T.sub.g) in the upper layer, a first holding period at these condition to expel generated gases, and heating the upper layer with higher speed than the lower layer until a Littleton temperature is reached in the lower layer.