History/value of coin

[CallieGray]

This coin I found in a box of old shtuff we were going through today.  It appears to be pure silver, but I've never seen any coin like it before... its like a silver dollar of some sort, with someones head on the back.  It is dated from 1979, minted in Denver CO, and it has the letters FG next to the head on the bottom right.  The head is in some sort of undecagon shape.  On the eagle side, it of course has the classic American eagle and the olive branch, but in the background there is the earth on the top left, and the moon in the background.  Could this be some sort of moon-landing celebratory coin?  What is it worth?  

[cogar]

You have "1 of millions" that were minted with the idea it would replace the $1 bill ..... but the public said "shove it", we don' like it.

It is spendable anywhere, anyplace ..... or you might find someone to give you more than "face value" for it.

And ps, there are 3 or 4 different $1 coins currently in circulation, but most of them are stashed in boxes and drawers .... just like yours was 

[wendy177]

Susan B. Anthony dollar is a United States coin minted from 1979 to 1981, and again in 1999. 

[mart]

FG is probably the coins designer !!

[Rauville]

FG is probably the coins designer !!

Right you are...Frank Gasparro

The Denver Mint alone produced 288+ million of these in 1979. I think the only reason for their being today is the fact that they are used for change in vending machines that take bigger bills.

[CallieGray]

Thank you everyone