Hey guys been working with jewellery in cycles, was looking to see your thoughts?
I have tried a subtle bit of “faked” light splitting for the diamonds, but probably need to push it a little more, still looks like cubic zirconia.
rendered size is 3840x2160 at about 300 samples, took an hour on my old laptop lol
Harsh criticism is great, be mean: It’s helpful 
Looks great, the gold material may need a little bit of tweaking (check out some pics of real jewelry), maybe the edges on the ring shaped things could be less sharp, the diamonds look great to me, neat rendering!
i think the chain is somewhat thin in relation to the rings. the gold and scene can use some more reflections. you could use an environment-texture in your world settings.
Apart from what the others wrote i would suggest removing some of the empty are in the center of the image. I t makes the image look … well empty 
Good luck and a happy life to you and your four wifes!
Thanks Guys, I have made some tweaks to materials and set up some HDRI lighting, regarding the thickness of the chain this is made to real scale 
This is a 3D model of some jewellery I bought for my Girlfriend’s Birthday (Just the one)
Not sure what I could put in the middle. A neck maybe lol
Any ideas on getting decent light splitting on diamonds?
ok alright metalix… try out some-another composition(s). the composition guidelines under the display properties of your camera can be very helpful. check the title safe box. try to keep things inside the area. you use a vignette so your focus needs to be inside. following this composition-angle i would use the perspective guide (golden -something- guide by head) and a thirds guide. the thirds are a very common guideline for getting the right focus of your composition.
maybe tracking your camera to an empty will help you control your camera more.
what kind of refraction value do you use for the stones? crank it up to 2.741 for diamond and make your color 100% white. well furthermore you are the god of your creation. if you want sparkles, make them. use a mix of transparent/emitter shader.
a quick sample :
there are 2 sparkling lights on the scene. disable the ray-visibilities. only if you want them to show up select the camera ray. disabling rays of objects you do not use will speed up your rendering seriously.
if you wanna go crazy use a particle emitter :P. notes > short lifetime - no gravity - high normal velocity - damping …
have fun
Thank you to everyone, I have had to file this project so I can move on, I did add sparkles in photoshop, and it’s all done and dusted.
I appreciate all the tips, they have been very helpful 
