Contemporary Papier Mache: Colorful Sculpture, Jewelry, and Home Accessories
You could create this with your own homemade papier mache or with an "instant" product like Celluclay. Just add water to Celluclay to create a papier mache pulp. You could also use an air-dry clay such as Creative Paperclay or some homemade cold porcelain. Just about any no-bake clay product should work well and may give you a smoother texture than papier mache (if that was desired).
I see all sorts of possibilities with this idea and I hope you do too!
Part 1. Materials list
Part 2. Making the bangle
Part 3. Decoupage instructions