Diamond prices are down 60% since a 2011 high, and they are still falling. It's not all down to lab-grown diamonds, demand is down too, especially in China.
No one can lab-grow gold yet, so its rarity and scarcity protect its value, but that will end too. It's just a question of when. China launched an asteroid touch-down mission this week, which will make it the 4th country/region to do so, after Europe, the US & Japan.
How soon will it be feasible to mine asteroids? Who knows, but a breakthrough in space propulsion might mean the prospect happens quickly when it does. It's possible gold has twenty years or less of being high value left.
The $80 Billion Diamond Market Crash Leaves De Beers Reeling
The processing cost is negligible compared the sales prices. Same as the cost of raw diamonds.
Diamonds are mostly a scam to part people from their money for literally a shiny rock.
it is, but if they maintain a monopoly, then cheaper raw diamonds will only increase profit.
although I'm assuming cheap synthetic diamonds are processed in other places.
Yeah, that's what I mean. People have been overpaying for diamonds for a very long time, mostly because they buy a diamond specifically because it's expensive.
A diamond isn't 1000x better at being a shiny piece of glass on top of an engagement ring than e.g. a cubic zirconia. But it's about 1000x better at showing that you paid 1000x the amount of money that you would have paid for a cubic zirconia.
And because of that, if the price of raw diamonds drops, the price of processed diamonds won't change significantly, because the production cost of e.g. a diamond ring doesn't matter for the asking price.