Why is lutetium counted as one of the rare earth elements?

In spite of all of the hand waving (incorrect) rationales, including some incorrect explanations on Quora and Wikipedia, for placing lutetium and lawrencium with the rare earth (f-block) elements (which are actually less rare than some main group elements), scandium, yttrium, lutetium, and lawrencium are all d1-transition metals. read more

Lutetium is the heaviest, rarest, and most expensive lanthanide element. The lanthanide elements make up Row 6 of the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. The lanthanides are pulled out into a separate row at the bottom of the table. read more