I can't remember finding a coin like this. Is this some kind of environmental damage or is something else going on here? I used my coin microscope to get these pics but for some odd reason it just wasn't as good as I can usually get. It appears to be pitted, rusted, or delaminated in spots.Obverse and reverse are affected. Any thoughts from the community?
Yes, but coins only rust if they contain iron, as with wartime steel cents. Rust is an iron-specific term, and a misnomer for corrosion of elements other than iron. For example, steel rusts because iron content is high, however, other metals oxidize visibly, yet do not rust . . . aluminum, tin, zinc, copper, silver, titanium, zinc, gold, etc. I find it difficult to tell from your images whether your coin exhibits copper wash from a mint process, or if it has reacted with something after it left the mint. In any case, because Washington Quarters are copper and nickel, your coin is not rusted.
Also.. Clad quarters contain Cupro-Nickel. The Copper mixed with the Nickel will tone if harshly exposed. Or burned with extreme heat.
It does sort of look to me like I see multiple de-laminated areas where the copper layer may be exposed, making the coin more red in those particular areas.
Yes it was hard to get decent pictures. I tried different angles and lighting but nothing could get a really good, clear pic. Here's a couple more I should have loaded up. Still not great for whatever reason but still....
Yep, that's corrosion. (As @ToughCOINS said, "rust" is specific to iron and its alloys.) Nickel is more chemically active than copper, so acids or other corrosive agents can attack it faster. The metal left behind is richer in copper and looks more copper-colored.
I'll just question whether it truly is corrosion we're looking at, as opposed to missing flakes of the CUNI sandwich layer . . . I think I see hard edges where that layer is missing. Corrosion would almost certainly have left soft edges because surface tension would pull the solvent upward at those edges, like the meniscus in a cylinder.
reminds me of when I was taking zinc cents and putting in muriatic acid with other coins just to see what happens. Of course, the other nickels, dimes, quarters I would just reintroduce to distribution because I didn't want to keep them .. they were icky looking. I have a thread in the past here about doing a bunch of them to show the effects. It's amazing the total unlimited post mint damage that can occur to distributing coinage whether on purpose or accidental.
You could be right. But it doesn't look to me like the brown patches are all deep enough to expose the copper core, and I have seen sharp-edged corrosion pits. In fact, it seems to me I see them more often than soft-edged ones. I could be misremembering, though.
I've seen coins that got zapped with electrical current end up with corrosive looking pits like that. Not saying that's the case here, but maybe it's one possibility.
The correct term is corrosion. And yes, you're looking at corrosion. Rust is a generic term but the same general idea. Every metal will corrode over time if exposed to the right environment. The quarter in question could have been exposed to salt water either in the ocean or dropped on the street in the winter. I've even pull coins like that out of pool drains (chlorinated pool water).
Rust is a form of oxidation. It is limited to iron and steel. Rust is more damaging because it can flake off and expose new metal. Aluminum makes a protective coating that is thin and allows the metal to be seen through it without any color change. It forms instantly.
I have collected for over 60 years and at times I feel like I don’t know a thing. Keep at it and you will get better as practice makes perfect but that really doesn’t apply to coins. It does help though.
