Carbon Spots and Grading 1 1

[Christopher Ray]

Afternoon all,

Quick question. Just acquired a lovely little copper farthing coin, but there's some obtrusive carbon spotting on the reverse. Is that something NGC conservation can deal with? If not, will the coin be graded as a details, or have a reduced grading because of it?

Cheers for any pointers.

[Christopher Ray]

Sorry, posted in the wrong section. Mods please move as appropriate.

Cheers

[Sandon]

   Welcome to the NGC chat board.

   NGC will most likely answer your inquiry by telling you that they cannot assess a coin without your submitting it for grading. 

   While it would be helpful to the members of the chat board if you would post a clear, cropped photo of the coin, I will endeavor to answer your question in general terms.  "Conservation" as I understand it means the removal of residues or other foreign substances from the surface of the coin that have not chemically bonded with the coin metal to form a compound.  "Carbon spotting" on a copper coin would usually mean that a contaminant, such as oil from a person's fingers, has chemically reacted with the copper to form black spots. Such spots cannot be removed without damaging the coin's surface, so the coin could not be improved in appearance by "conservation". Soaking the coin in a neutral solvent such as acetone may help prevent additional degradation.

  Grading services have given numerical mint state grades to many uncirculated coins with "carbon spots", although noticeable spotting will reduce the grade.  If raised corrosion products have appeared in or along with the spots, the coin will likely be "Details" graded with qualifiers such as "Corrosion" or "Environmental Damage".

   

[NickiO CS]

Hello @Christopher Ray, 

Thank you for reaching out to us. As mentioned above by a helpful forum member, we cannot predict the outcome of conservation or grading without proper evaluation of your coin. The spots you are seeing suggest that there is contamination on the coin's surface. If the contaminant has caused damage, NCS can stabilize a coin’s surfaces and prevent further damage, it cannot reverse corrosion that has already occurred. 

Damage to a coin's surface will likely affect the grade and may result in a details grade. The graders would need to examine the coin for a final determination. 

If you need any help with how to submit your coin, please let us know. 

Have a great day!