> I don't recall this part of the enumerated powers of the federal government from when I read the constitution. Has there been a recent amendment?
No, it's in the bare unamended text:
βThe Congress shall have power [...] To coin money, regulate the value thereof, and of foreign coin, and fix the standard of weights and measuresβ (Art. I, Sec. 8; emphasis added)
I don't recall this part of the enumerated powers of the federal government from when I read the constitution. Has there been a recent amendment?