LMC 1988-D RPM?

Hi Pete - it may be zinc rot along the face edge of the coin. Zincolns are susceptible to this kind of event and makes identification very tough. I'm sure you've noticed that some of the coins tagged at CC have the rot. That said, a coin in hand shows things a photo doesn't. Try getting approximately right on the location and then use the die marker to help dial in.

Yes - mint mark. Sorry about that. It was getting late and the brain was getting foggy as well.

I'm in your position weekly. When I CRH, I will take subject specimens for variety identification and set them aside. So many of the early 80s (but through out as well) have the corrosion problem along the face edge of the field/MM. I see the corrosion spreading in a generally even outcropping from the MM which adds to the delusion and sometimes made even more difficult when the copper plate rolls back over onto itself; looks like raised material. The vast majority end up being rot unfortunately, but I've released dozens that had me scratching my head. I hope I didn't let too many get away, but that being said, how long before identification would be impossible rendering the point moot.

I'm interested in what others are doing to this regard as well.

Thanks for the suggestion John1. I tried it and here is the result. I am noticing the roughness along the groove, but I am not sure what that means other than some rot/corrosion. Thoughts?

John1