I have compiled a list of sources for the elements that are available to the amateur chemist. Yttrium will be discussed here.
Yttrium is a reactive gray metal with properties very similar to the rare eath metals. It reacts slowly with hot water and dissolves quickly in acids to form a colorless solution containing trivalent yttrium. It is also found in the same ores with all of the other rare earth metals. Yttrium, though, does not have an f orbital like the rare earth metals and so has some differences. Yttrium, like most rare earth metals, is slightly toxic. Inhaling large amounts of yttrium oxide dust, just like any other form of dust, can cause lung problems.
In element form: Some spark plugs contain about 5% yttrium. They are normally marketed as yttrium spark plugs.
In compound form: Yttrium oxide is doped with europium oxide to create red phosphors in CRT screens and CFL bulbs. Yttrium vanadate doped with europium is used in mercury vapor lamp phosphors.
Here is my sample of yttrium. It is the ground wire from a yttrium spark plug. Since the remainder is nickel, I could not leach the yttrium out by hydrochloric acid.