Can anyone help me identify what is going on with this Roosevelt Dime? There is what looks like a raised brown spot right in the middle of the coin. Is this considered a CUD? Why would it be brown? Is that copper showing through? It is still sealed in the US Mint packaging.
I'm not sure what it could be but it's definitely not a Cud. Maybe a foreign material that got stuck on the surface or struck through into the clad surface. A Cud is a die break. When the edge of the die breaks off and strikes the blank Planchet the metal will flow into the void of the die. It would appear raised on the coin. It usually involves the edge and flows into the field. Here are examples from my collection and a book on true Cuds..
To me it has the appearance of retained strike-through plastic seen here https://www.error-ref.com/retained_strike-thrus__struck-in_errors___plastic/
Definitely not a cud. Hard to tell from the photos. Please leave in the mint packaging. It could be a number of things.
Without seeing in hand it could be a retained strike thru, (debris of some sort). Personally, I think it is corrosion. Remove the coin and take some clearer photos.
Thank you everyone for the responses on this! Update on the coin - I tapped it very lightly with my finger and the dark spot started breaking up, leaving a brown powder substance inside with the dime. It does seem to be some sort of debris / or corrosion build up.
If it is powdery then the only way to preserve whats left of the surfaces is to remove the coin and soak it in distilled water, let dry, and then give it an acetone bath. Picks would be best when you remove it, neither distilled water or acetone will hurt the coin. No rubbing.
