Quote - can somebody do a render of a multifaceted diamond on a diffuse/specular surface using
sunlite or spotlite?  I tried it in maxwell render but it came out all grainy (didn't know how to use it).

Try to put your diamond in a tight box or sphere. Make sure there is not too mutch light-bouncing in your environment (walls/ceiling without reflections). Give the rays a chance to find your diamond :)

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