Green stuff

I'm curious what causes this blue-green stuff, and what is it? To be clear, this is not verdigris. It does not damage the coin and you can easily remove it with a fingernail. I see this on a lot of coins of different metal types.

 

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What gives you the inclination that it not verdigris?

 

PVC goo is also green.

 

Looks like "Patina".

 

My understanding is that verdigris damages the coin. This is just superficial, easily removed and doesn't seem to affect the coin at all. I also see it on silver and copper nickel coins.

 

I've seen this on coins too but usually I can't remove that.

 

Sometimes PVC can cause verdigris. Sometimes verdigris comes off in "plates" when held together by PVC goo. I suggest an acetone bath. That should remove any PVC, and any plates of verdigris held on by the PVC. Anything that remains after the bath is definitely verdigris.

 

Susan L. Maltby has an artical in last weeks Coinworld about PVC-- Sept. 30, 2024 pg 30.

Apparently she prefers orderless mineral spirits over acetone for dealing with PVC.

That looks more like verdigris to me however.

 

Verdigris does not have to be tightly adhered. If you are in a dryer climate it may take the form of a powdery substance as you describe. It is still verdigris.

PVC has a more "oily" look. I have seen coins with PVC that had been treated with acetone but the job wasn't finished, and they too had a whitish-green substance in the hidden areas like you show, but it wasn't as deep green as yours.

 

If you treat it with VerdiCare and it comes off it was verdigris, if it stays on, it was patina, but you are now protected in any case...right @BadThad

 

It wasn’t there when the coin was minted so it should be removed carefully.

 

That's definitely verdigris. It is affecting the coin, it's pulling copper out to make the verdigris.

 

But isn't verdigris only on copper or bronze? Because I see this on silver too. It's usually along the rim and it always comes off easily without leaving any noticeable damage.

 

When you say silver, are you referring to silver coinage? Verdigris can form on copper alloys. I'm almost certain that includes silver coinage. Even though this is considered a silver alloy, it is so because silver is the primary metal. The majority of the remaining metal is copper.

 

Yes I do mean silver coinage. And your picture didn't come through.

 

Apologies, I just wanted to show you verdigris on silver coinage. Hopefully this time it posts. Not my image. These are 720 not 90%, but silver alloy( with copper) all the same.

 

If there is copper in the silver alloy, it will have a chance of developing verdigris.

 

PVC products are a mainstay for flexible plastics. If the package of transparent coin holders or boxes you toss regular coins into are high in PVC and any small amounts of water/moisture is there, verdigris will react over time. There are coin holders that are PVC free and if the moisture is very low you will probably not have a problem, but do your coins sleep with a vaporizer going or you live in an area with a lot of moisture in the air, put the coins in a food bag that doesn't leak water because if it can't leak water sitting on a plate, it won't allow it to get in to react with a coin. IMO, Jim

Or you can come to a desert with an average rain of less than a couple of in./year

 

It doesn't matter which alloy, if copper is present, verdigris can potentially form. No alloy is perfectly uniform. I've seen flecks of verdigris on gold coins!

 

It doesn't matter where you live but a drier climate helps. I'm fan of using layers for coin storage, e.g.:

1) coin holder (I like Airtite brand)
2) coin folder or album
3) put into freezer bag with desiccant pack and sacrificial copper cent
4) put that into a, heavy-duty poly bag - cheap on amazon!
5) Tight sealing tote, I like the water proof ones with locking top

Store in a location with the least temperature swings. It's the changes in temperature that often catalyze the bad reactions.