Hi! I am making some wedding rings out of 80% gold and 20% platinum. What is the proper hallmark(s) for this alloy? Thanks!
You could mark it 18K, or mark the actual alloy, AU800 PT200. Or do both, if you like. But I would skip the karat mark myself as unnecessary since while it meets legal requirements for 18K, it isnt actually 18K… You could also use just AU800 and not mention the platinum. Probably cannot use only PT200, as it does not meet recognized minimums for a standard platinum alloy on its own.
Thanks, that makes sense!