You won't believe what this plutonium pellet is worth. Wikimedia Commons Gold means luxury right? The precious metal is widely associated with royalty and wealth.

Turns out the stuff is actually a lot cheaper than some other rare commodities.

There are plenty of expensive substances out there, and unlike gold, they actually have some real personal or industrial uses.

These are the 16 most expensive substances we could find, by weight.

Think we missed something? Let us know in the comments.