TED Talks
Ted: Ted Ed: Why Is Glass Transparent?
If you look through your glasses, binoculars or a window, you see the world on the other side. How is it that something so solid can be so invisible? Mark Miodownik melts the scientific secret behind amorphous solids. [4:08]
Wikimedia
Wikipedia: Amorphous Solid
This page from the Wikipedia encyclopedia on amorphous solids contains information on examples of, the difference between amorphous solids and crystalline solid, and the transition between a very viscous liquid and an amorphous solid.