Dysprosium was discovered in 1886, through such an elaborate process that even a 19th century chemist thought it was over-the-top. And that technique wasn’t enough. It took another seventy years to get dysprosium on its own.
Paul Émile Lecoq de Boisbaudran clearly learned patience by writing out his own name, and so when it came to chemistry, nothing would faze him. He discovered gallium in 1875. That was nothing. Gallium is famous for having a distinctive melting point—chemists used to prank their colleagues by giving them teaspoons out of gallium which would dissolve when put in tea. He discovered samarium in 1879. That was harder. He had to use fractional separation, a technique that involves putting two mixed liquids in a column and separating them by vaporizing them, then condensing them, then vaporizing them again and condensing them again all the way up the column until the final sample that condenses is pure.
He went after element 66 on the periodic table in 1886. It was showing up as an impurity in erbium oxide, and he knew it was a new element, but it never seemed to separate out. He tried precipitating using ammonia. Then he tried it again. He knew that it was a metal, and many metals form insoluble precipitations in oxalate salt. He tried that. He tried it again.
In the end it took 32 rounds with the ammonia, and then another 26 rounds with the salt to get a sample of the element. Boisbaudran ended up calling it “dysprosium,” from the Greek word “dysprositos,” meaning, “hard to get.”
He didn’t know the half of it. Pure dysprosium wasn’t gathered at all in the 19th century, or for a good while afterwards. It was only a process called ion exchange chromatography, during which either a negative probe is used to attract positive ions, or a positive probe used to attract negative ones, that allowed chemists to get their hands on pure metallic dysprosium. That was in the 1950s.