Produced in melting furnaces, it is made up of raw materials such as silica sand, soda and nepheline to which coloring oxides such as sodium carbonate, zinc oxide, cadmium sulphide, nickel, etc. are added. The product presents itself differently depending on the processing of the same raw material or of the raw materials processed in a different way, it can be glossy, semi-transparent or opaque, with different finishes and more or less intense shades depending on the quantity of dye. The resulting products can be of various families:

1. sandblasted, with the characteristic <<dot>> finish;
2. slightly transparent and opalescent with coppery reflections that reflect differently in the light;
3. colored and opaque glass paste (enamel) which creates a non-homogeneous and uniform finish;
4. iridescent enamel on the surface that responds differently to light depending on opacity and materiality.