The glass (which does not crystallize even though it is accepted) of a window is NOT a mineral, since it is neither a substance of natural origin (although it is manufactured from natural components) nor does it have a defined crystalline structure, that is, the atoms they are not arranged in an orderly and regular way along axes and planes forming flat faces that keep a symmetry.
Remember that a mineral is defined as a solid, inorganic, homogeneous substance, of natural origin, with a crystalline structure and a determined and well-defined chemical composition within narrow margins and that has regular and characteristic physical properties.
Explanation: No, glass is not a mineral. ... Definable chemical composition: SiO2 *Actually, most industrially-produced glass is not pure silica, but having impurities is still a definable chemical composition so this part of the definition is ok. Orderly arrangement of atoms in a lattice: NO.
