So...I found this today and got it into a 2x2 right away. Any guesses as to what we are seeing? It's gold toned front and back. It's not plated over, and it has no color variations that you would normally see with environmental toning. The pictures definitely don't do justice to the color.
There is no rule which states that color variations are normal when a coin is subjected to environmental conditions. More often than not, toning caused by environmental conditions remains pretty much the same. Personally, I think your quarter has toned due to ordinary handling while in circulation. Chris
Could it be a formerly gold plated quarters that the TV guys were pushing? One of my coworkers found one of the platinum plated quarters and asked me why the mint was still producing silver quarters because the reeds didn't show the copper band.
The long shot possibility is the experimental manganese/zinc planchet they struck in 1999 got dropped in to the 2003 bin st some point. I know my pictures don't show it very well, but it really does resemble that variant quite a lot.
Very long shot considering that manganese and zinc are both silver/nickel in color. This is assuming that your coin is clad and shows the copper layer on the edge.