OTTOMH - You need to use high specularity, large spec halo, high diffusion, refraction 105 or more (important), reflection around 20%, transparency 80% with a subtle rainbow transparency tint (use random on the DTE mat). The transparency and reflection will vary depending on the hue of the surroundings, but this should give you roughly the right look. If it's still too "clean", use blurred reflections on premium-64 or above. Hiking up the TIR can also work well for detailed scenes. Good luck.