Hi, Rob; I believe you've come across a clad coin which has turned brown. The cladding on a quarter or dime, which I believe is nickel, turns brown and eventually, red, if it is a quarter or dime dating from 1965 up to the present. Left exposed to the elements or buried deeper in the ground for enough years, it will demonstrate a dull, heavy, coppery color; especially if you attempt to clean it up a little. As an avid metal detectorist, I live in a world of brown nickels, dimes and quarters. Rob, welcome to my world... If you have a quarter you'd like to use to verify this information, bury it in your backyard for 5 or 6 years; come back, dig it up; brown, coppery-looking coin! Real silver coins are so much more fun. Finding a gold coin, as well the coin gods know, would be the most fun and they seldom, if ever turn brown.
Mr. Rick, Don't bet the farm on that proposition. Lo, the coin you depict isn't missing anything... It has merely turned, .....brown.
@Rick Stachowski is a very knowledgeable error/variety specialist. The coin he posted is not environmental damage, it is a true missing clad layer error. However, you are correct that the overwhelming majority of "copper" nickels, dimes and quarters posted by new collectors suffer environmental discoloration. They will have discoloration on both sides as well as the rim, and will also weigh within the tolerances for a normal coin. BTW: what kind if farm are you wagering?
Clad coins and Nickels are Cupro-Nickel composition. 75% Copper and 25% Nickel. Here are my Metal Detected Environmental Toning Damaged coins -
You are incorrect. That is definitely a missing clad layer error. Here are more examples from my collection - There is a difference so you need to educate yourself on identifying what is Environmental Toning damage vs. Missing Clas Layer. http://www.error-ref.com/missing-full-clad-before-strike/ I will bet my entire farm with cows on it