Close ring gap

Beschreibung des Auftrags

My wife's stainless steel wedding ring originally had a stone set in it. This one was lost, two further attempts led to the same result. I would now like to close the gap, so that a normal ring is created. He would have to do this by approx 1 mm dilated, what the stone originally did. Is something like that possible?, If yes, How high are the costs. Or you can insert a stone, that lasts PERMANENTLY?