Looks like Environmental Damage due to the elements. I metal detect and find many Nickels such as yours.
You actually had a metal detector NICKLE find graded spending all that $$$? Or is this just my misunderstanding?
NO Environmental Damaged coins are not errors.. but Improperly Annealed coins are. Very big difference
YES They once had them on HSN for the ridiculous price of $249.95 http://www.hsn.com/coins-currency/1959-jefferson-nickel-black-beauty-error-coin_p-4489137_xp.aspx
I have a few other nickels that I would like to post a photo of to get oppinions. Anyone interested in looking at them?