The destruction of the network of covalent bonds of a chalcogenide melt, which causes a transition from semiconductor to metallic conductivity, may be described from a unified standpoint in the case of both high-resistivity and low-resistivity melts. Metallization of chalcogenide melts limits the range of glass formation with respect to the component concentrations and the structural-transition temperature. The use of high rates of cooling from various temperatures of melts in which a semiconductor-metal transition occurs with an increase in temperature makes it possible to obtain a given material both in the form of semiconducting glass and in the form of amorphous metal.