What Is That Green Ick On Some Of The US Large Cents And Other Copper Coins

The green 'ick' is most probably verdigris, commonly known among coin collectors as 'copper (or bronze) disease'.

Chemically, it is a complex copper salt of copper hydroxy carbonate. If it appears as small clumpy or pimply growths, avoid the coin like the plague as you said in your OP. Underneath those growths, you will almost certainly find tiny corrosion pits in the surface of the coin.

You must keep keep such coins well away from other coins in your collection, because such corrosion can spread to them. Almost of the value is lost.

Curiously, with larger ancient coins, if the green appears faintly, as an even green tinge over the whole of the coin, some regard that as attractive eye appeal, and it can actually enhance the value of the coin. This rather attractive patina, when it appears on copper roofing of public buildings, is much admired.

I've seen some beautiful all green large cents where the green is a hard toning as opposed to verdigris.

Rather than being corrosive, they are similar to those with the dark toning that actually helps protect the surface.

Photos of what you are referring to might be helpful.

Thanks for all of your responses. I can understand a coin that has a green glow to it. That is probably toning of a sort. But what I was referring to are the patches around the devices and sometimes actually on the larger raised areas. From what you've said, these are corrosion locations on the coin. Yes, I have put a few Lincoln Cents in a jar with these problems, along with coins without any visible problems, and a few months later, the unblemished coins were showing signs of the green ick.

For the most part, I see this problem is very common on the Lincoln Cents minted after 1982. They seem to deteriorate at a very rapid rate, including signs of the green ick. For those cents prior to 1982, they also show this green ick, but they don't seem to succumb quite as rapidly.

I do collect Lincoln Cents, and stay away from anything detracting. As with my US Braided Hair Large Cents, I collect only choice specimens of a grade. What I mean by that is there is no unusual discolouration, no major nicks, rims are as clean as possible, etc. Most of all, the coins should catch my attention due to its condition, Great eye appeal.

So, the green ick is something I avoid like the plague. I was pretty sure it was corrosion, but needed to ask.

I look to fill my gaps in the US Braided Hair Large Cents several times a month, but I am running into the green ick even on coins that have been slabbed by PCGS. Apparently they don't think it is something detracting for grading purposes. I guess the green they are seeing might just be oils and dirt. But that still makes me shy away because it takes away from the total eye appeal of the coin. It's pretty frustrating to not see a coin for months that meets my critical eye, but I guess that is part of the fun of collecting.

Thanks for providing all of your opinions and knowledge. I am a bit more educated now. Caley Ann

I don't own any slabbed coins with green ick. Like I said, I avoid those like the plague. I just could not believe TPGing services slabbed coins with such stuff. Like I said, it probably isn't corrosion in those slabs, but just oil and dirt.

The Statue Of Liberty needed a very extensive restoration due to corrosion.
Steel skeleton (frame), with copper cladding.
Not a good combination of metals.

OK, here is a picture I pulled off the internet. This is a US Braided Hair Large Cent reverse which has what I call the green ick. Exactly what is it, if it is not corrosion?

Actually, some of those IHCs I bought looked so nasty under a loupe that, at one point, I gave most of them a bath. Don't know if it really killed any germs but it made me feel better, lol.

Your lg cent does look a little severe, though. Maybe, it does have some pitting along with the ick.