Animated coloured scanning electron micrograph (SEM) of Fractured glass edge and surface. Glass is an amorphous material that lacks a periodic crystal structure. It is a fused composite of silica and small amounts of other minerals. Properties of glass vary by modifying composition and production techniques. The combination of mechanical, chemical, optical, and thermal properties is important when determining the best type of glass for a product. The non-corrosive nature of glass makes it suitable for storing chemicals. Its regular crystalline lattice allows it to fracture cleanly when scored. A high lead content makes glass soft and easily cut or scratched.