Praseodymium comes from the process of separating several elements from each other. In 841 Mosander pulled didymium from lanthana. In 1874 Per Teodor Cleve discovered that didymium was still two elements together. In 1879 Lecoq de Boisbaydran pulled samarium from didymium and found samarskite. Finally in 1885 Carl Auer von Welsbach was able to separate didymium into two elements one of which was praseodymium.
When Praseodymium is mixed with magnesium it creates high-strength metals found in aircraft engines. The element is used mixed with many other elements to created substances to slow light pulses down allows fluoride glass to be used as fiber optical amplifiers. To invest in praseodymium all one has to do invest in rare earth elements. Or, invest in the goods with which it is used.