I don't know if you have glanced at a Periodic Table recently, but Lithium is on the far left hand side and far distant from anything marked "rare earth" much less the "rare earth metals" (which are primarily just right hand of the center-line). As element number 3 on the periodic table it's also per some basic interesting Big Bang statistics the third most common element in the universe. Admittedly most of the universe's Lithium at this point has settled into various compounds which are regularly called "salts" (a short, common name, because they are so common), though household table salt is usually Lithium's "big brother" on the periodic table Sodium, but Lithium itself is still just about as common as dirt on this planet even if don't tend to sprinkle it haphazardly on our foods.