[jjnoakes]

You can't make new rare elements out of thin air though.

[meowkit]

If you had enough energy and the right equipment/process you could "alchemize" gold or any other element out of Oxygen/Carbon/Nitrogen.

[everfree]

Sure you can. Create a new chemical and call it a "rare substance". It will probably get about as little traction as the long tail of 99% of the cryptocurrencies out there.