It's a rare earth, which are really odd elements.
The name dysprosium is the equivalent in English of "unobtanium" which is used frequently in American movies as a McGuffin (i.e. a plot device that moves the action along without being too specific on what it is that everyone is after.)

From our friend wikipedia:
Quote
In 1878, erbium ores were found to contain the oxides of holmium and thulium. French chemist Paul Émile Lecoq de Boisbaudran, while working with holmium oxide, separated dysprosium oxide from it in Paris in 1886.[11] His procedure for isolating the dysprosium involved dissolving dysprosium oxide in acid, then adding ammonia to precipitate the hydroxide. He was only able to isolate dysprosium from its oxide after more than 30 attempts at his procedure. Upon succeeding, he named the element dysprosium from the Greek dysprositos, meaning "hard to get". However, the element was not isolated in relatively pure form until after the development of ion exchange techniques by Frank Spedding at Iowa State University in the early 1950s.[2]

In 1950, Glenn T. Seaborg, Albert Ghiorso, and Stanley G. Thompson bombarded 241Am with helium ions, which produced atoms with an atomic number of 97 and which closely resembled the neighboring lanthanide terbium. Because terbium was named after Ytterby, the city in which it and several other elements were discovered, this new element was named berkelium for the city in which it was synthesized. However, when the research team synthesized element 98, they could not think of a good analogy for dysprosium, and instead named the element californium in honor of the state in which it was synthesized. The research team went on to "point out that, in recognition of the fact that dysprosium is named on the basis of a Greek word meaning 'difficult to get at,' that the searchers for another element a century ago found it difficult to get to California."[12]
It is used in nuclear fuel rods and has many desirable properties as a shield. Hence, in it's way, it's doing the same job as lead, just for a different wavelength.

If you really study the Periodic Table, it really holds a wealth of detail and information and is an amazing construct in terms of understanding the real world.
cool
Artemis


History is easy once you've lived it. - Duncan MacLeod
Writing history is easy once you've lived it. - Artemis