1942-S Mercury Dime - Weird Rim Deformations? 0

[Woods020]

I picked up a 1942-S Mercury Dime today, and as I was giving it a once over while putting it in a 2x2 I noticed what initially appeared to be material peeling around the majority of the reverse around the rim. Some areas look like cuds, and others are peeling and flaking it seems. I did notice a die break on the obverse that is probably unrelated. What is your opinion on what is going on here? I tried to get the best pictures possible, but I am learning that light reflects off the rim in a way that makes it harder than the interior of the coin.

[Greenstang]

Looks to me like it is a rim fin that has been folded over. 

[Woods020]

11 minutes ago, Greenstang said:

Looks to me like it is a rim fin that has been folded over. 

It is almost as if there was an extra layer that is not adhered around the edge. I am relatively new to this so I am sure I am not describing it properly, but it wasn't something I have seen so far.

[Greenstang]

You have partially described what a Rim Fin or Finning as some call it. It is a thin flange of the metal that extends over the edge of the coin usually caused by excessive striking pressure which causes the metal to squeeze out of the thin gap between the die neck and the collar. Once these have been put into circulation, the fin gets folded over the rim.  Not much value once they have been folded over but if you can find one that isn't folded, then you would have one with some value.

Nice photos showing where it is folded over.

[Woods020]

I just did some reading on rim finning. Thanks for steering me in the right direction.