@CerberaMy hardware is very low specs and my patience for long renders also low
But for this particular render (more than a year old) I think I had set a very blurry reflective floor and background, so no matter the settings there would always be a grain.
Somehow the grain for this particular render gives me the impression of a more realistic depiction reminiscent of old photographs and that effect gets more justified with the low lighting giving the center object a more jewel-like character on display which I wasn't intended for but rather intended for an abstract object.