I have been pondering for a while upon how mirrors and reflections work. In a standard shiny metal, metallic bonding allows electrons to be free of atoms and thus occupy any energy level. This means that electrons can absorb the photon and re-emit it as the same frequency. However, I still do not understand how a non-metallic surface (for example a thin sheet of plastic at a very low angle) can reflect light as well as how gold manages to reflect light but also have a gold colour apparently added to the light simultaneously.
Any responses/references to reading material would be greatly appreciated.