Glass is not a mineral because it does not have a definite chemical composition, which means it does not always have the same chemical composition that can be expressed by a chemical formula. It also does not have a crystalline structure, so there is no specific order to the atoms.
According to Encyclopedia Britannica, glass is an inorganic solid material that is typically transparent or translucent and is hard, brittle and resistant to most conditions. Glass is an amorphous solid, so it does not have a crystalline structure, and the atoms and molecules are not arranged in a specific order. Glass is made by rapidly cooling molten ingredients like silica sand to prevent visible crystals from forming.