After working on 3D flaws and inclusions in diamonds on a render that got featured, I decided that it was time to create an outstanding colored gemstones collection, and achieve it by procedural means... The result is here. As I explain in the tutorial, some gemstones do have some underlying geometry to provide the best looking results, I think you will agree. All the rest is node based. I used the real world INDEX of REFRACTION for each mineral, and the result is here to speak. RENDERS in CYCLES.
Diamond, Corundum (Ruby, sapphire and color sapphire), Beryl, Tourmaline (with real life double refraction setup), Quartz, Opal (works for light and dark and all colored shines), Malachite, Lapislazuli (with inclusions), Agate (works for all colors), Pearl, Turquoise (with or without pirite and dirt inclusions).
The opal is one of the hardest material to reproduce in 3D, but I think my solution is one of the best available (and maybe simply the best), capable of delivering light and dark opals in a wide range of colors and varieties. Nodes are grouped and organized to make tweaking easier for each material. Some gemstones have several materials to create the right sets of flaws and inclusions.
I specially loved creating this collection, it will work wonders for your gemstones, sculptures, characters jewellery and more!