So on a ring like that, I'd expect to get at least 100% of spot on the gold...and I say at least because that is the type of ring that jewelers buy for the diamonds to discard the gold.
The problem is the markup on stones and labor. While a ring like that may cost 14 grand or so if buying it at the store, you are paying the diamond broker, the goldsmith, the refiner, the jewelers rent, etc. It's like buying a new car, you drive it off the lot and half of it's value disappears.
Anyone care sharing how much wholesale diamonds like that sell for by the carat? I see them a plenty, but it's just to chemically strip away the gold so that I can send the diamonds back to the jeweler....I never really know what the stones are worth.