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
It's good to see diamond mining being replaced by artificial diamond manufacturing, which appears to be better envitonmentally and socially.
But I wouldn't compare diamonds to gold. Because gold is an element that can't be manufactured (without a particule accelerator and an insane amount of energy).
Asteroid mining is still science fiction.
Right? Diamond is a crystal of Carbon. Its synthesis was a challenge, required high pressure, but sounde doable from the beggining.
Now, transmuting one element into other (gold)... That's atomic energy right there. A whole new level.