I have a friend who is a jeweler. He has one of those little kiosks in the middle of a mall. He's really good. I don't know about other jewelry kiosks, but those little huts are dirt cheap compared to a corner spot and that tends to keep prices cheap.
When I bought a diamond to ask someone for her hand (but not her vagina, that was apparently off limits 
) I went straight to him. His markup was approximately 2x on diamonds. The big name jewelry shops with the corner space outside Macy's are usually more like a 2.5x or 3x markup. His deal for me was his cost plus 10% so I ended up getting a $3200 ring for $1800.
For comparison, look up what a Bulova watch costs at Kay versus directly from Bulova on Amazon. Think more like 10x markup. I got a $1200 retail watch directly from Bulova for $181. And I know what you're thinking... "are you sure it wasn't Belova or Buleva?" Yes I'm sure.
Used is really a great way to go. He did show me a ring that he had there used. 5.1ct solitaire with an additional 2ct in channel sets. Original retail was $18k, but he was reselling it on consignment for $5100. If I had $5100 at the time, maybe the vagina wouldn't have been so off limits (I'm completely kidding, by the way. My ex remarried a woman, so no amount of rock would have changed that. She also gave back the ring after 14 years of marriage which I thought was generous. Respect.)
With the fragility of so many marriages these days, the superstition about used rocks is real and it drives prices way down. I don't care about superstition, and if a marriage IMO shouldn't be held together with the glue of material pretense. If someone bought me a ring, I'd be more impressed by their fiscal responsibility in getting me $18k worth of ring for $5100.
Research online, poke around Kiosks instead of glitzy storefronts, heck... troll CL and FB marketplace for runaway bride scenarios. Have a jeweler set it how you want it. As has been mentioned, gold is gold. It is basically currency turned into jewelry, and there are actually laws that say jewelers must give fair market price for gold (not that they all follow the rules). It's likely you can get a 1:1 trade for the gold part, so you're paying for labor and setting for a diamond you bought cheap and can inspect in person locally.
Thank you for all of the advice, I appreciate all of it. The potential new SWMBO was a Geology major and a total rock nerd, so natural diamond is important to her. That being said, she likes the color in them and is totally cool with used and unusual gemstones. We are looking at a completely custom setting with teal Montana sapphires, which we have located at a fair price. I will look into every option given!
In reply to Javelin :
Remember, the only way to be sure it is a real diamond is because of its imperfections. If there is no imperfections it is probably fake.
Similarly, you (and she) is not without imperfections. If you present yourself as no imperfections, you too are probably faking it.
In reply to Javelin :
This is another good reason to look at used diamonds and used settings, old stuff can be more interesting and unique to someone who can appreciate it. My wife and I pieced together her ring out of an Art Deco platinum setting from the 20's, and a diamond out of an (ugly) brooch inherited from her great-grandmother. The diamond is antique, hand cut in a Miner's Cut, and has a load more character than something new from a department store.
I didn't know much of anything about the rocks other than my firmly held belief that they're entirely overrated. I still believe that but, your post inspired me to do some research on the picking out of the blingbling rock. Depending on your timeline, jamesallen.com is running a 25% off sale for another 4.5 days (as of this post) that excludes loose stones. Their filters are more user friendly than Blue Nile, more and better pictures/videos, and similar prices.
John Welsh said:
In reply to Javelin :
Remember, the only way to be sure it is a real diamond is because of its imperfections. If there is no imperfections it is probably fake.
Similarly, you (and she) is not without imperfections. If you present yourself as no imperfections, you too are probably faking it.
If there are no imperfections, it's likely a figment of your imagination. Even lab-grown diamonds can have flaws and inclusions.
All I know is they are an absolute ripoff created by the DeBeers. When I used to handle PAP policies, people used to get extrememly pissed when I told them I can replace the ring, that they paid $10k for and insured it for that much, for $5500.
We know they aren't scarce, we know the conditions under which they are mined and how the workers who mine them are treated......................yet everyone keeps buying them.
Absolutely blows my mind.
