Chinese steelmaker HBIS in yuan-denominated iron ore deal with Brazil's Vale

Not to overdramatize, but this is exactly what you'd start looking for as the begin of the end for US dominance internationally.

"China is the world’s biggest iron ore consumer and has been trying to increase its influence over pricing of the steelmaking raw material, for which contracts are usually in dollars, and the Vale deal marks the first yuan-denominated deal for HBIS with an overseas ore supplier."