DeBeers hoards diamonds because short supply equals higher retail prices. Cecil Rhodes began the practice himself in 1888-89.
Plus the wholesalers collude to fix prices. The international diamond cartel is one of the few than hasn’t been driven out of existence by law enforcement.
Gem-quality stones are rarer than industrial diamonds by a factor of about eight (8). Yet gems cost hundred of times more than industrial diamonds because of the hoarding, the price-fixing, and a 100-200% retail markup.
It hasn’t been that long that there was no standard, diamond or otherwise, for engagement rings. It was only after WWII, when DeBeers decided to roll the dice on a high-dollar ad campaign (because their sales were in a slump) that an advert copywriter came up with what some consider the greatest advertising campaign ever: A diamond is forever. Implying that if you give her a diamond engagement ring, you intend to be married to her ... forever. Sigh!
And that’s why the hideously overpriced diamond engagement ring is to this day a cultural landmark: an ad campaign.
I hope that the lab grown diamonds put them out of business...............FOREVER!.............