Using acrylic, I made a batch of decorative gems for craft projects.
They’re on Thingiverse at http://www.thingiverse.com/thing:618889
I was cutting these in clear (or tinted) acrylics with a backing of silver or gold cardboard.
While trying different materials, I found a nice looking and cheap combination. Laser-ply covered with a sheet of thin aluminium adhesive insulation tape. Etching burns away the tape to leave tiny scorched mirrors.
It reminds me of Indian Shisha mirror designs.
This kind of tape:
(Usual disclaimer about lasers, hazardous materials, safety, etc)