If you end up going with a diamond, you might consider a company like Brilliant Earth [1], which offers "conflict free" diamonds (and other gems), and recycled precious metals. Their gems come from mines that employ adults at reasonable wages. I'm not associated with the company, but they made my fiance's engagement ring and we're very happy with it.
Thank you for the link! I've been trying to find a decent source for conflict-free diamonds, and this seems to fit the bill. I hope I can convince my girlfriend to go with an alternative, but this is likely a battle that I will lose.
The issue centres around the social stigma of not having a diamond ring. Friends and family will ask what the stone is, and need to be educated. And no matter what you tell them, the perception will be that I was too cheap to buy her a real engagement ring. Nevermind the fact that I'm not actually saving any money, I'm just spending it somewhat more wisely.
It's actually a little bit of a stressful situation for me. I'm in the Royal Canadian Mint's MintChip Challenge, and I'm hoping to win some gold from the competition, so I can melt it down and make an engagement ring for her from that. In my eyes, that has more meaning behind it. Moreover, she's going on a trip with her sister to Prague & Rome in a month, a few days before our 7 year anniversary. Since she knows a proposal is coming, I was hoping to surprise her by showing up in Rome and proposing to her there. May not be the wisest way to spend my money, especially when I'm not exactly swimming in cash right now, but I felt it would be worth it for the memory and moment. To me, that's a better use for my money than some artificially-valued diamond. Seems like I'll have to scrap that plan and save more money for the ring she wants.
I've been trying to find a decent source for conflict-free diamonds
You can request Canadian diamonds at the jewelry store. My store had to overnight a collection in for us to look at, but it wasn't an issue for either of us.
Canada's diamond mines have labor and environmental standards to abide by and Canadian diamonds are laser inscribed with a goose logo and come with an extra certification being from Canada. De Beers does own 2 out of the 6 mines in Canada, but it does not have anything near a monopoly there.
You could do the economist thing and try to phrase it in terms of opportunity cost. That is, by insisting on a diamond, she's giving up a moissanite stone that's 5 times the size; by insisting on an uncultured diamond she's giving up a diamond that's twice the size (and more pure to boot).
Speaking as a girl without even the least bit of interest in diamonds, "If you give up the thing you want, you can get a thing you don't want that's TWICE AS BIG" is just in no way a selling point, especially as long as her association with those stones is that they're fakes. You can try to make the moissanite seem cooler, or the lab diamond more ethical, but women are already aware that if you buy "fake" jewelry, you can get bigger stones, and generally that's just seen as trashy.
Real people do not behave as the homo-economicus of economics papers would have you believe. Especially when it comes to life-altering choices and the signs and symbols associated with them.
Short version: do not do this, for it will rebound on you horribly.
This is the intersection between Macro economic theories (op cost) and consumer behavior. And that too, one of the most emotionally charged decisions people make in their life times - marriage.
I would be extremely hesitant about using that particular gambit.
Went through the same thing with my wife. In the end I caved and just bought the best damn diamond I could find after 3 months of searching. Easier to explain why you bought an alternative stone than why you bought a shitty diamond.
Sounds like a good way to show off. "Oh look you have a diamond ring too? Did it come from one of those sweatshop mines where children have to work? No? Oh that's a shame. Mine came from an ethical mine".
My wife and I got our wedding rings here (we also have the luxury of living in the Bay Area, so we got to meet with them in person). They also have a truly astonishing array of vintage rings with stunning stones and settings. If your fiancé(e) is into that style, they have the added benefit of being both glamourous and unusually inexpensive for the quality (and it’s definitely not a “fake”)!
[1] http://www.brilliantearth.com/conflict-free-diamonds/