Thanks for your kind words Balt!
Your render turned out very nice as well! I really like that opal.
One tip that might help give your diamonds a lift if you have an hdri with some black areas your diamonds will have more contrast. You might have to play around with the orientation of the hdri in order to get the best compromise between your stones having some contrast and your metal not looking strange but it will make a difference. I think that your diamonds are reflecting back the grey in the hdri and that is making them look grey and washing out their dispersion 'fire'.
... and tilt that opal up so we can get a look at it

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Thanks for sharing!