The most striking thing you notice about this metal is how absurdly light it feels in hand. While lithium is lighter it is, frankly, useless as a metal proper because it's so reactive and soft. Beryllium is neither of those two things. What it is is hideously expensive and supremely difficult to work with. Only a few companies in the world have the expertise (or the clientele) to deal with Be. 

Much also has been said about its toxicity. A lungful of beryllium dust is bad, bad news. Pulmonary edema, or close to it, is the lifelong diagnosis of berylliosis. But then again, you really don't want a lungful of any metal dust. If you can avoid the questionable temptation to take a file to your precious little piece of beryllium then you have nothing to worry about. There once was a guy who bought himself a bike whose frame was made out of beryllium. It weighed all of two pounds and it entered bicycle lore henceforth. The cost? A cool $25,000.

That works out to $27 a gram if you ignore the labor cost involved in making that bike. You'll find our price for beryllium much more palatable!

CAS 7440-41-7