RhinoArtisan with Rhino DOF & Filmic - www.cadwax.co.uk
The light dispersion (Abbe number) effect is missing, otherwise the diamond looks fake.
It’s important for a truly realistic rendering (Rhino/Cycles perhaps doesn’t allow this).
I guess the point was for RhinoArtisian. Otherwise, one would have just used bella, which they also sell! It would be an instantly superior render with I imagine 3 material, and one lighting change.