That's exactly what makes most of the rare earth elements "rare": they are common in the Earth's crust but rarely concentrated into easily mined deposits. Neody

That's exactly what makes most of the rare earth elements "rare": they are common in the Earth's crust but rarely concentrated into easily mined deposits. Neodymium and praseodymium are also more common than tin but significantly more costly than tin because they don't form ore bodies like tin does under geochemical influences. https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth...