According to Wikipedia rhenium holds the title of rarest of the stable, naturally occurring metals with a concentration of only 0.7 parts per billion in the earth's crust. That's six times rarer than gold! This precious metal is very resistant to corrosion and has a very high melting point making it perfect for many applications.... if only it wasn't so rare and expensive! NASA and the Pentagon though have generous budgets which is why they can afford to use a large portion of all the tiny amount of rhenium mined every year to go into jet engines and rockets. Claim your little bit 'o the stuff for your collection before the Gov hogs up every last piece of it :-)
A one gram bead (or two half gram beads) of pure rhenium goes into each round container.