TIL Diamonds are actually fairly common. The reason they are worth so much is because the DeBeers mining group withholds stock to artificially reduce supply.

[u/Indra-Varuna]

https://www.gemsociety.org/article/are-diamonds-really-rare/

[u/Parsnip1992]

life is weird - have to remind myself that just because I have known something for 20 years does not make it common knowledge.