Guys, I have a copper clad 1974 half from a batch of halves I got from my credit union to spend around town, and I have one from that batch, that has the copper center, but is tarnished black, like silver tarnishes on front and back. So I was wondering, is there a possibility that this half could have the same silver top layers as the 1965-1970 silver clad halves were made of, as a mistake? Or is it just the way cupronickel clad tarnishes? I believe I have seen post-silver dimes, quarters, and even nickels like this, but was never sure what exactly caused the tarnish. (I may have even seen some Ikes like this, but never any SBAs. Guess SBAs are too new for them to make an alloy mistake with them. Sorry, don't have the equipment to post any pictures.
I would say that it is all but impossible that you have a blank that was four years old before being minted. But I couldn't say what caused the darkening to occur. My guess is that it was somehow chemically attacked in some manor. What do the surfaces look like, a chemical attack would generally leave the coin with a somewhat porous surface.
Oh, then it probably is a chemical attack, seeing as, if I look up close, I can see small silver dots all over it, which would describe it as you said, as porous. Thanks for the tip. I knew it was nothing of value, but I just found it strange that it would look tarnished like silver, yet have a copper core.
My guess is the chemical was sodium hyper-chloride, an industrial bleach used in natural gas fields to treat waste water. Household bleach will also have this effect over time. Keep searching those rolls. I wish I still had the time to do that.
I found this in a CWR. 1974D. Not a good image has some faint rainbow like colors you can't see here. Same weight as a 2001.
