These were donated for a Child's Play auction.
To get the effect, start with an opaque blank insert (I find black works best). Have at hand a disposable spoon and a smal, sealable container with some dish soap and water you can agitate to make tons of bubbles.
Using an aplicator (I use a flat silicone brush), apply a very thin layer of UV resin. Use the spoon to scoop the soap bubbles onto the resin-coated surface. Quickly put it under a UV light to cure the resin. I clean any overspill with a craft blade to keep it neat.
Once all facets are done, brush the mica powder of your choice onto all the surfaces and cast in clear resin.