Glass is a material that has been used for centuries for a variety of purposes, from windows to decorative items. It is made up of several ingredients, including SAND, silex, SILICA, and frit. SAND is a naturally occurring granular material composed of finely divided rock and mineral particles. Silex is a type of sedimentary rock composed of quartz and other minerals. SILICA is a compound made up of silicon and oxygen atoms. Frit is a glass-like material made by melting and then cooling SILICA and other materials. All of these ingredients are essential for making glass.