This is both a pricey and delicate element. Although it is nowhere near as reactive as the alkali metals, europium is nevertheless the most easily tarnished of the lanthanides and will rust readily in air forming greenish oxides. On top of its chemical reactivity europium is also soft and extremely rare making its demand as a pure metal essentially nil.

The vast majority of rare earth metals come from chief ore monazite, a type of sand that is reasonably abundant. However, even here Eu got the short end of the stick as typical yields top out at about 0.05% by ore weight compared to almost 50% lanthanum and cerium! This means that after the arduous process of putting all that sand through acid baths and centrifuges for each ton of lanthanum or cerium hauled away in a box car the tech hands over an envelope with a pitiful couple of ounces of europium. It's not hard to see why all these factors taken together leave europium as one of the most exotic metals in existence.

Note additional options for this element on the Ampules section

CAS 7440-53-1