I bought some wheat pennies recently and found this: Does anyone know what this could be? It doesn't seem the right color to be gold plated, but you never know.
Ya, I thought that too, but it doesn't look like the original copper at all. I don't think it is toning or gold plating.
You're right, it does not have the right color. It could be plated in silver, but more likely it's plated in zinc. This is a very popular chemistry experiment that many students do in school. It involves zinc in water that has dissolved sodium hydroxide. Zinc will coat the outside of the copper penny, giving it a "silvery" appearance. This "silver" penny is then heated. In this process, the zinc and copper atoms begin to mix. The atoms of each metal will "substitute" one another, and at an atomic scale it might look like a checkerboard, where copper and zinc atoms are jumbled together instead of being separated. The cent will then take on a "golden" appearance. The copper and zinc will have formed a substitutional alloy, and this mixture of the two metals is brass. I believe the brass can wear off of these over time, so that may have left a slight golden tinge on your coin. If it only silver-colored, then either the brass wore off completely or the coin may have been left at the zinc-coated stage.
I'll have to try to find the procedure somewhere I remember bookmarking some videos on YouTube that detailed the procedure quite well!
I have done this many times with classes. Lots of fun but be VERY careful, hot solutions of caustic are dangerous!
