1.  Main types of materials used

Glass

Inorganic, non-metallic material, obtained by complete fusion of raw materials at high temperature, into a homogeneous liquid which then cools to a rigid state, essentially without crystallization. Glass objects can be plain or decorated.

Ceramics

Mixture of inorganic materials, usually with a high clay or silicate content, possibly with small amounts of organic matter added. Ceramic objects are first formed and the resulting shape is permanently fixed by firing. They can be glazed and/or decorated.