Quiz# 8 Natural or Artificial toning?

PVC damage is a "film" of different thicknesses. It is not soft.

 

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I have always considered that Green residue a type of verdigris from the 10% copper in the coin. It is not dry and hard like a patina on brass or bronze. This type is soft and wax-like, possible due to the lack of or very low concentration of oxygen or mixing with other chemicals from being stored in plastics. Most plastics are a byproduct of oil.
It can form on gold coins also due to the 10% copper content in some of them. I would say that coin has been in the same storage condition for a long time and the green has occurred naturally. JMO
I have had several silver coins that turn my acetone green while soaking.

 

I will go with NT. I have seen such coins come out of original hoards in a humid but sulfur poor environments. Same environment but sulfur rich produces toning/corrosion to the point of black. So my answer is poorly stored in humid environment, but NT to that extent. Not intentionally placed there.

 

Hey now you leave her alone... she just wants to look like the Statue of Liberty.

 

Green and black. Natural ugly and some crud to go with

 

I actually agree with Doug on something! Miracles do exist! He is correct on this aspect—Silver coins definitely do get verdigris from environmental damage. Also, I agree with him in that verdigris and green toning can look similar, but all green toning is not verdigris environmental damage. In this case, I would have to see the coin in hand to determine if it was, indeed, environmental damage. In this case, my gut says damage, but it could just be crusty green toning. Is that toning attractive? Generally not considered desirable.

 

Would you be kind enough to post entire photos of both sides before and after?
Thank you!

 

Whatever the toning, I wouldn't want that coin in my collection.

 

NO. Homey can't play dat game. I'm set up to take micrographs. I'm not going to go to the trouble to change anything to show things that (IMHO as the OP) are not necessary to see.

 

What about red dots on gold coins?

 

They are called "copper spots." They are detracting. Up until about fifteen years ago, they were only seen on genuine gold coins.

 

Great question! Something I wanted to know.

 

Great answer! Something I wanted to know.

 

Thanks. Great then I don't need to worry.

 

Chemistry stuff...the plasticizer for PVC is dioctyl phthlate (DOP). This is a very thick oily substance that gets between the polymer chains of the PVC and allow them to slip over each other, making it a pliable polymer. The DOP is a colorless liquid, however, it isn't very volatile, so it's going to stick around awhile and entrap other substances the coin might encounter and hold them close to the coin's surface.

 

Many coins sent in old flips have clear, sticky droplets on their surface and in the holder! Some empty flips have a greenish ring where the coin was after it is removed.

 

I've seen a lot of those at small coin shows.....well not recently.

 

I've removed both proof and mint set coins from their original mint holders and found those same ring deposits left over. I assume those are also PVC rings.

 

I have saved a couple of very old flips with that greenish ring of glop. I saved them to remind me just in case I should ever be dumb enough to put a coin in a vinyl flip again.