Iron Pyrite Nugget

For grid work. Pyrite, which is iron sulfide, has been easily confused with gold. Hence, the nickname, Fool's Gold. It gets its name from the Greek pyr meaning fire because it gives off sparks when hit with a metal. 
It is believed that possession of pyrite attracts money. Some use Pyrite to stimulate the intellect and enhance recall of information. Good for those of us who can be forgetful.