Encapsulating a coin with active corrosion

Ya see, read Halperin.
Read JA.

Not to mention, you contradicted yourself via your earlier statements.

Who you know and for how long is of no consequence or germane to the non-factual statements you have a habit of stating as absolute truth.

You again...re. TPG comments... expand on your constant you know better diatribe.

You are wrong, in fact you are absolutely misleading collectors with this statement:

It is a given you would also state this:

You can benefit from reading the commentaries and public information made available by the various TPGs on their websites concerning the subject.

I have zero problem with your well known penchant for braggadocio. Many of us do so. However, when it is based on absurd and self-contradictory statements that young hobbyists without enough experience assume is fact because you stated the opinion, that is what I have and have had an issue with, for many years.

I don't mind your condescension. We all have personality quirks.

With all your years of experience, and numismatic expertise, why does it now via this thread , become clear you are incorrect, on one of the most impactful issues in coin collecting: verdigris? You have made the same statements on CT in the last couple of years and I have taken exception. You were not aware? Do you not read any commentary on any other numismatic website or articles/books on the subject? There are many. It is a known issue and has been for many years.

 

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The formation of verdigris completely hinges on water which is naturally acidic due to the absorption of carbon dioxide:



The first mass to form is composed of hydroxides and carbonates of copper.

 

My understanding is that these slabs are not hermetically sealed. So... particularly in an extremely humid environment, couldn't the verdigris have appeared after the coin was slabbed?

 

Are you saying the corrosive process will be sustained even if the coin is placed in a vacuum?

 

Regardless of the environment, if there any feed materials at all, the process has all it needs to further attack the metal within that mass.

Verdigris is primarily composed of ionic compounds. On a macro scale it appears like it's just a normal, stagnant mass of material. However, on the smallest of scales of chemistry, that mass is very active due to the ionic charge imbalances contained within.

Given the verdigris is also connected to a metal (which in itself is feed material) - there's a constant fight to reach equilibrium on an electrochemical scale. Even something like a 0.1° change in temperature "stirs the pot" and pushes the equilibrium in the other direction. The more dynamic the ambient conditions, the more active the mass will be.

Generally, I do not recommend a vacuum for storing coins. I've debated this topic a billion times on the internet and do not wish to again but I'll state my position: A vacuum is an invitation to allowing air in and eventually IT WILL. Mother Nature always wins. Even the using the best laboratory conditions and equipment - vacuums leak. This creates a dynamic atmosphere and dynamic conditions can drive the corrosive process be it with air, temperature, or other complicated reactions within a mass of verdigris.

 

In a sustained vacuum, the equilibrium would shift toward CuO, I'd guess, with water offgassing. But, as @BadThad said, you can't keep one.

 

Why do you disseminate such opinions? How would you possibly know or verify such a statement, to justify it is implying fact?

It is another of your typical multiyear anti-TPG curmudgeon statements.

 

Just a simple question. Is this Bronze disease?
Looks a lot like verdigris.

 

Verdigris is any type of copper corrosion - "bronze disease" is just a name coined by some to describe the corrosive process. The end result is still the formation of verdigris.