Glass

 Glass is a material which stands our from competing ones due to some important features: it has a noncrystalline amorphous molecular structure which yields the material behavior of an undercooled viscous melt without discernible melting point. It is extremely brittle and is liable to crack and disintegrate as a result even of minimal superficial blemishes. Hence, particular safety measures are required for most glass constructions. On the other hand, there are different methods of tempering glass which result in an enhanced behaviour under stress and increased security. The most prominent property of glass is, of course, its transparency, which makes it suitable for some important functions, like allowing for through-view and for penetration of light and solar energy, which are beyond the scope of other materials.