Because synthetic diamonds are indistinguishable to the naked eye (IIRC a trained eye with a magnifying glass can spot faint nitrogen impurities which are characteristic of natural diamonds) the thing you're really paying for is the piece of paper, the certificate. You're not really paying for carbon allotrope.

So it's less like gold which is fungible and a more natural form of money.

Diamonds feel more like an NFT...

Agreed. So much so I wonder if they engrave all lab-grown ones, so they don’t get mixed up easily with mined and ruin their price.

If I'm not mistaken, diamonds get etched with a serial number when they get graded so you can look up the history later.

In fact, De Beers have been agressively hiring for their osn blockchain-for-diamonds project.

god the blockchain hype cancer never ends

More importantly, you're paying for the human rights violations. Hopefully, synthetic diamonds eventually become popular enough to destroy the perverse incentives fueling the traditional diamond trade.

While yes, you are literally paying for the certificate, what you're really paying for is propagandized emotion.

The diamond cartel did a great job equating "real", mined diamonds with love and romance. For some couples, unfortunately, lab-grown just doesn't have the same feel to it.

The maybe overly terse parent comment is referring to this concept:

https://en.wikipedia.org/wiki/Veblen_good

Not really. The comment is talking about price increasing with the quality of the "good", which is perfectly conventional. The weird price cliff is especially out of place for a Veblen good.

No, Veblen bad.