RE: RE: Clarification re REEs...You are strongly mistaken. Rare earth elements are classified on the basis of similar chemical properties and grouped together as such (e.g. lanthanides). Elements such as Ta and Nb belong to another chemical group known as the HFSEs (high field strength elements) that also include other metals such as Hf and Ti.
It is better to use the term "exotic metals" for metals that are economically important, but rare and do dot belong to the ferrous, precious, energy, or base metals group.
REEs are often found along with Ta, Nb, etc. in carbonatite deposits though.