After covering up the Garnet Gel in my last project, I decided to try to a similar texture with cheaper materials. I went to the pet store and got a bag of the smallest aquarium gravel I could find. Here's what I did.
Paint it, rocks and all, with black acrylic paint. (I didn't paint the hot pink rocks before adding Opals and wished I had.)
Paint glue on places that you want to put Opals. Sprinkle Opals on the wet glue and heat with heat gun until Opals melt. Add pinches of other Opal colors. Spray black areas with interference Radiant Rains.