Extra Window on Monticello
Question: I happened across a 1970 nickel. On the back, upon further review I noticed that the Monticello had an extra window. When looking at the back it's located on the right side just above the center window. It may be nothing, but I thought I would ask. I had purchased an old jewelry box at an estate sale and found a small box of coins. I know nothing about coins and I was browsing your sight and looking at the pictures and mint markings etc..
Without seeing the nickel, or at least a good image of the coin, I am afraid I will not be of much help to you.
Many things can go wrong when minting coins, and it could be a mint error of some sort. If this is the case, your nickel would probably have an increase in value, however the value would depend on how unique and rare the error is.
It could also be some sort of post-mint damage or altering, in which case it would be worth face value.
If it is some sort of doubling error, it seems strange to me that the doubling would only be of the one window.
It could also be just one of those strange things that happen when minting coins, such as with the Wisconsin State Quarter, some of which have an extra leaf. (click on the image to see a larger view)