I saw that one after I created some diamonds a while ago.

I only reallly used a mentar ray dgs material and played with the settings and got the following pic.

I created the scene as I saw a animation of some diamonds dropping that someone did in mental ray and wanted to re-create the look of it (I didn't use caustics for the render as I didn't know how at the time).

If you want the material settings then give me a shout and i'll post them up.

heres the pic