@Dan i think you're already very good.
@Fletch i've checked and yes there is, but it does not work as i want in that scene. As you know it's depends a lot on lighting.
Anyway here is the library i've made long time ago. I really doubt it's useful for somebody, but maybe for fun...
The first nine are for faint interference effect while the last five are "strong". For this kind of material is really important to know what you want to achieve and the lighting + set up.