The preparation of the vitrifiable mixture forming the glass takes place in melting furnaces at temperatures between 2,192 and 2,912°F (1,200 and 1,600°C). It begins with the melting (transition to the liquid state) of the mixture followed by its refining that eliminates the gaseous compounds linked to the chemical reactions produced during melting. After the homogenization of the vitreous mass, the conditioning is the final step that lowers it to a temperature of 1,832 to 2,372°F (1,000 to 1,300°C) compatible with its subsequent use.