Well I just did a mock up using copper. I laminated 1mm of copper onto some silver wire and rolled it down to well over 4x its length and the copper is clear and bright. I used various abrasives going through the grades from very coarse to fine and still no rub through.

I have made the purchase, opting for the 18ct rather than 14ct for a better colour. I will post pics if it works out ok!