This poor coin has had it.. But, I have never seen something like this.. The D mintmark is sticking way out.. What is this called??
D for Damaged It's a Copper Plated Zinc Planchet. The plating around the mint mark has been compromised and the inner zinc in that area will rot. Like this -
No, no, no Paddy.. I have some just like the pics you just posted.. The D is sticking out from the coin.. Let me go back and get it just to make sure.. I'm going to double check on this.. Thanks
Do a rubbing, with a lead pencil, and see if it is sticking up any higher than the other devices. Probably not, and being a crappy zincoln, Paddy is most likely correct.
As the zinc is exposed to the environment, the corrosion products can expand and push up the copper plating. It's similar to rust on a car, bubbling up the paint.