Back in 2001, I was participating in Jewelry contest where I tried to mimic real-world techniques of photography to make Jewelry renderings. I even made tutorial on this subject http://kezan.eu/tutorial/
Since then I made couple models, textures, materials, rendering environment, rendering settings, always in a different way to see how it will look like.
Now I decided to make Brilliant Cut Gem as close as possible to real "perfect" cut dimensions, with quads only, easy to customize chamfer and be able to use Subdivisional Level of Iteration without changing the shape of a model. You can see that girdle is perfect round while other facets are perfectly flat. The UWV Mapping is Unwrapped on a single tile, just to see how a painting of this model for real-time engine could be. So here it is ;) More info on model at https://www.turbosquid.com/3d-models/brilliant-diamond-cut-3d-model-1210533 or at http://kezan.eu/project/brilliant-cut-diamond/