Quote - Crystan, you'll find diamond in the Gemstone material drop-down list, which will set the IOR for you. Personally I do not set it to Hyper Realistic.

There was a setting for Pearls but it was on the old Daz site, so cannot find it for you. There is a IOR setting for pearl in the same drop-down list though.

Sharkbyte, funny how we both rendered redheads with the simular poses.

The problem is that the IOR alone isn't really giving the effect I was after. It just looks like glass but the background beyond looks a bit more bulbous than usual. I was really looking for some thin film settings which aren't added by the drop-down so I can get that same irridescence normally associated with shiny gemstones. Well, the render didn't come out too badly in the end regardless. I just have a bit of extra postworking to do.