I have a quarter that looks like it’s not clad on either side. It’s looks like copper. Suppose it could be a science experiment. Thoughts?
Looks like a science experiment. You could try some copper polish/ketchup and see if you can brighten the plating (which looks to be flaking). No harm since it's a spender.
Clad is Cupro-Nickel.. 75% Copper and 25% Nickel. The Copper will environmentally tone with longtime exposure to the elements. Here are Metal Detected examples from my collection.. Nickels are also Cupro-Nickel nickel and suffer the same fate with Environmental Exposure damage.
I wish I got a dime for every time these specific reference pix had to be posted. I'd be rich. Double rich if I got a dime for every "missing clad" thread featuring coins suffering from the elements were posted.
I think you have your answer, so I will just welcome you to CT and thank you for posting your photos as full image.
Rust, environmental damage, metal detecting find. If you look at your own OP you can see the layer is there especially on the bottom rims of both sides. A quarter missing a clad layer (about 100% 1 side only) the copper will be very bright (not dirty and rusty) and the details will be crisp from the strike. It will also be thinner and weigh less from the missing metal. If you weighed your coin you will see it is within tolerance for US clad quarters and not missing a clad layer. Missing 2 clad layers would be VERY VERY rare. as well as very thin, very light and the pressure from the strike on such a thin copper core may result in some hideous monster coin.
Not a missing clad error. It was soaked in acid. I used to do this all the time in the university chem lab
