A shader I improvised for a Crysal Mare thread.
The result is ... meh. It doesn't look like in the show and the diffraction effect only look good with certain backgrounds and at certain distance - it will require some more work before I can add a decent Crystal Pony in the game.
Weirdly enough, I couldn't find a single SFM/Gmod model for a Crystal Horse (even just the mane&tail). That's why Rarity got volunteered for this experiment.
Video (38 Mo)