Restricting the export of lutetium oxide but not of crystals made from it could fairly obviously be described as an attempt to get the making of crystals moved to China.
Just to give a near random example, there used to be a factory in Texas which made the lutetium crystals that are at the heart of magnetic resonance imaging machines.
The lutetium oxide from which the crystals are made (in only a slightly updated process from the way we all made copper sulphate crystals in high school chemistry classes) all came from China.
Exactly what is a rare earth metal is very slightly arguable, some would say it is only the lanthanides, lanthanum, cerium through to lutetium in that little box at the bottom of the periodic table.