Thank you Jakadave,I know to be "more realistic"metal would need some fine scratch because nothing is perfet in real life, but it depend to our goal.If we want "ultra" realistic render or photo-realistic render. all professional photos and product shot are post worked to erase all these little and no beautifull scratch, to make product more perfect than in reality,to make dream people. so... but I agree with you , in my render metal are too "clean".thank you for your feed back
Thank you very bubbaloo, I really appreciate.
Q2 , thanks a lot. to answer to your question, the stone is "taken" between the two part of metal, which has the track of the stone too.I'am not a jewels expert, it was just a try, but maybe it's not enough. see the screenshot joined.
Thank you very much Tea bag.
Alex.