0.5kg of neodymium is around $200 and it's probably the cheapest of the rare earths
0.5kg of europium is around $3,750
Obviously lots of variation there, but maybe ratio of how much it costs vs the total cost of all the other minerals is a better metric to use here than pure weight
the reason the purified elements are expensive is that they're so hard to separate from each other
rare earth elements aren't actually rare
they're called that because we've inherited alchemical terminology from the 18th century when alchemists were first starting to discover that there were more than four elements, and that in particular there were several different kinds of earth, such as magnesia, silex, etc., and as it turns out things like thoria are in fact quite a bit rarer than silex
For the purposes of this conversation, which is about economics not geochemistry, they are in fact rare. At least the minerals are
They are not, in fact, rare, as is almost always pointed out when they are mentioned.
Regardless, they never show up in a pure form in nature so what we should really be looking at is how common minerals that they're easy to extract from are not how common the atom itself is. And the useful rare-earth minerals are indeed "rare"
The amount of magnesium in the human body is .1% by weight. That's not too far different from the amount of rare-earths in an EV.
In the case of a human, i would not wish magnesium deficiency on them, it is not fun, can have severe long-term consequences (such as death), and generally is something that medical professionals will find concerning.
In the case of an EV I don't know what the consequences of removing rare-earths would be, but the fact that it's a tiny percentage of total mass doesn't imply that they can just be dismissed.
