The funny thing is when people go to sell their gold jewelry they find out (even with the huge spike in gold prices) they overpaid a bunch and still can't get much money back. And if you purchased a gold ring with a diamond in it they toss the diamond back to you since it is worthless.
I have a cousin in the jewelry business. Typically, the markup on jewelry is 200-300%. (Or that's what it was a few years ago when we last talked about that business.)