Because the marketing goal of the diamond industry is to convince buyers that the amount of money you spent indicates how much you love your spouse.

Theoretically you could spend the same amount an some insanely huge used diamond.

"Used things are for poor people" - they know their market well and don't even have to actively diminish used diamonds/rings value, their customers do it for them.

Sustainability is a luxury belief. The market will change when such values disseminate more broadly.

But that doesn't dictate how much you're supposed to be paying for each individual diamond. If you have a "proof of love" budget of $6000 you could just buy five used diamonds instead. You could then start an arms race with other married couples and claim they don't love their spouses, because they only bought them a single diamond.

Edit: I checked and multi diamond cluster rings look way more impressive and make single diamond rings look cheap and icky.

The majority of people who understand that diamonds are a scam are not simultaneously attracted to diamonds.

How? You don't usually buy diamonds for yourself, so the person who understands the diamonds are a scam does not have to be the same person who is attracted to diamonds.

It’s far more common for people to collaborate on purchases like this than to surprise each other: you could go so far to say that people choose diamonds for themselves.

It can feel like a bad luck kind of thing. Basically the only reason someone would have to sell their wedding rings are divorce or some other downturn. And don't want to invite bad luck by buying it.

Similar to not buying clothing from someone deceased or a wedding dress from someone divorced.

Can argue that this is not very rational. But much about the wedding process isn't :)

Just gotta market it right. Maybe section off by length of marriage and dissolved by death or divorce.

A 60 year marriage, ended by death of one spouse shouldn't be unlucky. Especially if it was actually the death of both spouses in some tragically romantical way.

You bought me a train wreck diamond???

Don't underestimate the power of superstition.

> Basically the only reason someone would have to sell their wedding rings are divorce or some other downturn.

That's why your shop should only sell the weddings rings from people who had a long and successful marriage and died peacefully in their sleep at age 95.

Haha, yes indeed. It'll be the free-range eggs equivalent for buying jewelry. Ethically farmed from happy wedded couples.

I don't think people who insist on diamonds care about how they are sourced. After all the blood diamond thing didn't stop anyone. What people want is to be skillfully lied to.

The blood diamond thing stopped a lot of people. I’d say it was the primary reason people pointed to when they passed on diamonds. Now almost all the diamonds you buy are expressed certified as conflict free.

My wife wears my great grandmother's ring. I thought that she would not be interested but was elated when I discussed the option. When I was talking about marriage with my parents my mom mentioned that she had a couple rings I would be welcome to, but then mentioned: "one is from a very long and happy marriage, that would probably be best, the other...".