I am new to enameling and have been looking at the work of many different enamelist to see what effects are possible. This picture is of a piece by Diane Druin and I think it looks like mother of pearl on the inside. Is this effect one type of enamel like a opalescent or a mix of opaque and translucent enamels? I have looked in the limited instructional material I have and cannot find a clue to it. I have no fear of experimentation but am just assembling my enamels so knowing what to buy would be helpful. Thanks for any assistance.