Green scuzz on coins

[XpipedreamR]

Could you guys comment on possible causes of various green scuzz/corrosion/discoloration that can occur on different types of coins, silver, copper, and nickel?

 

 

I'm particularly curious about silver. I asked this question on another message board and that the consensus was that if it's silver, and it's green...then it's PVC.

 

 

I have a couple silver coins and a nickel that have a tiny little green point of mossy "corrosion." I can't believe that it's PVC because I don't believe that they've ever even been stored in PVC flips. It doesn't really look like PVC contamination to me, either.

 

 

Unfortunately...no pics

[Hoot]

The mossy spots are not PVC. They are spots that arise from the corrosive forces of moisture and atmospheric conditions surrounding the coin. They often point to an uneven mixture of metals or contamination of metals in the planchet. For instance, carbon is a common contaminant in metals, and it's also an element that has a high affinity for water molecules. Under the right conditions, carbon on the surface of the coin can gather water molecules from the air and cause localized corrosion, thus leading to the kind of spots that you are referring to. The spots can also be black and therefore look like raw carbon, thus the name.

 

Hoot

[TomB]

Hoot is correct but there is also the possibility of verdigris, especially on copper, nickel or clad (copper-nickel) coinage. This is a diseased state of copper made of cupric acetate that can effect nearby portions of metal. Lastly, could it be that the coins were stored in PVC holders before you owned them but that you are only now noticing the effects of the mis-handling?