I can not find any other errors like this. Would love to hear opinions or questions.
That is not an error, just some well placed tarnish or a piece organic matter on the coin.
It's not a piece of anything. It's in the coins, you can see it's the metal. But a chemical of some sort came across My mind.
struck thru with a piece of copper?
It will happen suddenly
Another theory, it had to happen in the striking processes. Something with the dye itself. Or someone being slick n making a cool ass quater with a chemical.
It could be a minor strike though that exposed the copper core of the cladding. Or it could be PMD (post mint damage). One would need to look under a glass to know for sure, no significant value add either way but sort of cool location. If a strike though maybe a 1$ in a 2x2 at an error dealers table they end up giving away to a YN if truly a strike though
11.5$ Southern Dollars, The little “Big Easy” set
It looks like a retained die chip...and could be a piece of core metal. Interesting effect, but no significant premium. Cheers, RickO