I saw these years ago and remembered them today and managed to find them again. Sometimes it's good to have ADHD. I could have just kept doing what I had planned to do at the time instead of just changing course and searching til these turned up again.
The artist is Desiree of Desired Creations, and she's done a lot of good tutorials on her site, but this is my favorite technique of the ones I know she's created. It looks like a Monarch Butterfly wing.
I love polymer clay, especially premo gold, but also the other pearlized clays. I always planned to make some of these and now that I've found the tutorial, I'll just have to buy more clay and get to work. :)