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
Well, you can make gold atoms (see here), but it takes many times more energy per atom because the energy contained in the bonds between neutrons and protons in the nucleous of atoms is many-fold the energy contained in the bonds between atoms (just see the difference in potency of conventional explosives - which release energy contained in the links between atoms - and fission and fusion bombs - which release the energy contained in the bonds within the atomic nucleous) hence it’s not really an economic viable way of making gold.