What causes this?

Not sure if this is an minting error or PMD. The arc is the same size as a quarter and appears copper in color.

 

Log in or Sign up to hide this ad.

It's the "Old PMD". This most definitely did NOT happen at the mint. Looks like another coin was sitting on it for awhile.

 

Thank you.

 

Just environmental damage. Another coin was on top of this coin when exposed to something, which left the mark. An interesting study is to put a few coins, overlaid, on a sunny windowsill and leave them for a month. When you look at them, you will see much the same as your coin.

 

What they said above.

 

I think it happened at the mint. I've seen the same thing on early South African shillings.

 

Huh? How early? Examples?

 

Found some examples of what Skip said
SOUTH AFRICA 1897 SILVER ONE SHILLING COIN (7570)On the baynow
https://www.ebay.com/itm/334598754994

 

Can you please explain this? It clearly looks like something, another coin, laid on top of it for some time leaving this mark. I for one, don’t understand how this could have happened at the mint.

 

It Can't.
Thread closed please.

 

Looks like a circle on the Obverse.
Some kind of ghosting. Nothing like the issue on the Quarter in question.

 

I just post em as I find em
The experts can evaluate
https://www.ebay.com/itm/2348573609...3RdCmW5Rq6&var=&widget_ver=artemis&media=COPY

 

Probably an abrasion or stain.

 

This is not an abrasion! The surfaces of the coins are 100% virgin. It is not PMD either. It is not a discoloration on the surface either. This characteristic has been driving me nuts for decades. The only coins I've see it on UNTIL NOW were from S.A. Mint.

 

But.. You're assuming it's the same issue as the Quarter in question.

 

I still don’t understand. When I look at the OP’s Tuskegee Quarter, the first photo it barely shows but if you look in the right spot it’s there. The last photo shows it more clearly, a light brown ring the same size as the quarter. Looking closely at that ring, in the center going from side to side, with the curve of the ring, there is a darker line following the same pattern. I can’t help but think something was lying on top of the OP’s Quarter. And I can’t get that out of my mind. The SA coin has totally different look than the OP’s coin. I’m not arguing with you, I’m just trying to understand.

 

I'm not arguing either. In the 1970's Charles Hoskins could have taken the coin to the Mint Lab in DC and found out the exact cause. I don't have a clue and only posted what I have seen under a microscope on some coins from S.A.

 

That's fine.. You should create a thread on the subject. I personally think it would be interesting to look at more and try to attribute the issue.

But IMHO it has nothing to do with the Quarter in question