Rendering a diamond as photo-realistically as possible is a 3D challenge. Light doesn’t just bounce off an object; it enters it, bends, changes color, bounces back and looses intensity. To achieve all this requires the use of Caustics to handle this refraction of light as it passes through a diamond and onto its supporting surface. Also, to more accurately re-create the physical behavior of light in the diamond requires the use of a dielectric material. And just to add that touch of realism which indirect illumination creates, Global Illumination and Final Gather also need to be used.