A picture would be needed to do the best pricing. It could be a wide variety of things like a capped die or struck through grease or even post mint damage.
Melissa, does it look something like this? http://cgi.ebay.com/ND-Jefferson-Ni...53?pt=Coins_US_Individual&hash=item5ada831cf1
there is no post mint damage that i can tell other than the defect and dirty due to i suspect circulation