From what I can make of the pictures, it appears to be a nice struck through grease. But as Rick said, better pics will confirm it.
Double sided grease covered die, if that is a possibility. I've not seen a mint error coin quite like this one. Is it possibly an adjustment strike?
IMHO Obverse looks like a very weak strike based on the lack of detail in Lincoln's hair, face and beard. It's all there but very flat looking. The reverse looks more like grease filled due to the missing details, and it's blurry/shadowy looking. Combine the two and you get adjustment/setup die strike. It's a good keeper!
I don't think it carries any kind of premium. Here is what the experts say about adjustment strikes and grease filled dies. http://www.ngccoin.com/news/viewarticle.aspx?NewsletterNewsArticleID=514
Just because it will not be slabbed with an official grade by the TPGs does not mean that they don't carry premiums. I still believe that this is only a struck through grease error and not a die adjustment strike, but considering it is on the more noticeable side of the error spectrum, it should still at least command a premium on ebay.