Vitreous
Vitreous refers to a material in a glassy state. In such a state, the constituent
atoms do not exhibit the long-range order that is characteristic of
crystals. However, they still exhibit short-range order -- the separation of atoms and/or the lengths of
covalent bonds are very close to their typical
equilibrium distances.
Under certain conditions, vitreous materials may begin to rearrange themselves into crystals. This process is referred to as devitrification.
See the entry on glass for more information.