1978 Penny Question

beetle662 · New Member

First off, let me say that I am a newbie here! I am not an avid coin collector, but spend my free time metal detecting. A by-product of that has been a growing fascination with coins!

I have a 1978 Lincoln Penny that has me somewhat perplexed.
I have posted it on other forums and so far the consensus seems to be that I should send it for grading and slabbing.

This penny shows a serious orange, almost gold color to it (more like brass maybe). The penny has not changed since the day I found it in my pocket back in 1978. Perhaps the best thing I ever did as a 10 year old kid was put this away for the future. Anyway, the penny is very detailed and has not corroded/faded/browned at all like other pennys do. I have weighed the penny and it comes in .02 grams LIGHTER than a "normal" penny from the same year. I would think that this should rule out the possibly of being plated. I would think plating would add weight and also cause the coin to lose some detail. Also notice that it is not properly aligned when "coin-flipped".

The scan isn't the best, but I think it gives you the basic idea on the coin.

Someone suggested that perhaps it was struck on the wrong planchet, one intended for a foriegn government perhaps.

What do you all think???

Bob P · Site Admin

Hi Beetle662,
First of all, welcome to the coppercoins forum. It is nice that you decided to visit us.
As far as your 1978 penny goes, it could be a number of things. The first is what they call a 'brass' cent. This chemical reaction occurs in a number of ways, including heating and chemical baths. Here is a very interesting link that explains how it is done. www.mailleartisans.org/articles/articledisplay.cgi?key=9114
As far as the weight differential of the coin, a chemical bath could lead to the weight reduction.
Of course, there is always the possiblity that it could be a planchet for a different world coin, but I am not so sure. Hope this helps a bit!

Robert · Senior Member

You need to find someone with a scanning electron microscope that has an Energy Dispersive Spectroscope attached to it. Most good-sized universities have one. Maybe some research companies do too.

They'd put it in a vacuum chamber and NON-DESTRUCTIVELY determine the metallic composition of the coin. It sholdn't hurt the coin. Don't let them put tape etc on it though. You want to preserve the coin as much as possible. I would also do a "normal" 1978 cent that's also unc.

To me there seem to be 2 possibilities. Either the odd coin is essentially a "normal" coin in terms of metal alloy (though slightly underweight) or the composition of the coin is *not* what it's supposed to be.

If the composition is significantly different than the "normal" cent, then I would say it's an off-planchet cent. I would then do research to determine which foreign coins were made by the US mint in '78 and compare that list and the composition of the odd cent to the coins in a Krause world coin catalog.

My prediction... it's very close to the specified composition but a little high in zinc. That is, it was a "bad" batch of copper that was used for a US cent.

But I may be wrong. That's just a guess.

beetle662 · New Member

I sure do thank you both for your remarks! I have a couple of larger Universities around me here, and I might give it a go. If not, a real good friend of mine teaches Biology at the University of South Alabama, so maybe I could get some help there when I visit him this spring.

This coin is just so odd.... it has me baffled to say the least.

Any other suggestions or comments are most certainly welcome! And I appreciate your efforts as well!