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Environmental Damage

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I submitted my first coins to NGS for grading and was disapointed that one was returned simply marked "Environmental Damage." No further explaination was given.


The coin is a 1781 North American Token (copper). It is very dark in color with a slight greenish cast. I'm interested in learning what "Environmental Damage" means and what I can do with this other wise very nice coin.


Your comments are appreciated.

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A copper coin with a "greenish cast" will not grade with NGC. Such a coin could be authenticated and encapsulated in an NCS Details Grade or Genuine holder.


When a copper coin is described as having a "greenish" color, one of two things are most often the culprit. Sometimes the green is caused by storage in PVC-laden holders. This residue can frequently be conserved off the surface. Assuming the residue has not eaten into the surface metal of the coin and there are no other surface problems, the coin should grade with NGC.


The other green color seen on copper coins is due to environmental conditions. Moisture in the air along with other elements in the coin's immediate environment can corrode the surface resulting in green growths or an even green patina. This type of environmental damage typically can not be removed through conservation and will result in a coin that will not grade with NGC. Certain types of this second type of green on a copper coin will actually protect the coin from further deterioration which can be seen most often on coins of age and often has a jade-like appearance.


There are a series of articles being included in the NCS eNewsletter further explaining some of the typical surface problems that one might encounter. Visit the NCS website at www.ncscoin.com to sign up for the newsletter and view previous issues.


Chris, NCS

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