1978 Lincoln Cents 2.5 gm (Thin)

[Vidroy Alkirk]

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[Vidroy Alkirk]

These 3 found over an 8-year period of agressive coin-roll hunting. The copper alloy appears to be normal for this date, but they are thin like a dime and weigh only 2.5 gm. I was wondering whether it might be a known variety.

[MintErrors]

These would be classified as a possible error.


Varieties can be reproduced from the same working die and there can be tens of thousands of the same variety. Errors are more unique and typically are not related to human error done on the working die. Varieties are typically doubled dies, repunched mint marks, over mint marks, repunched dates, over dates and a few others.

Errors are multiple struck, off center, broad strikes, mis aligned die, die caps, lamination, thin planchet, wrong metal/struck on wrong planchet, mated pair, wrong thickness stock, tapered planchet, struck though and quite a few more.

So there is nothing wrong with the reverse of these coins?

If you place a normal coin on top of one of these coins, are they the same diameter?

Using a normal cent, are they the same thickness?

Do they stick to a magnet? Careful do not damage the coin! Place a cloth or plastic between coin and magnet to keep it from scranching the coin if it is attracted to the magnet.

[Vidroy Alkirk]

Nothing wrong with the reverse. Their diameter is the same as a normal cent. These cents have reduced thickness compared to normal cents. They aren't magnetic.

[Vidroy Alkirk]

Three thin 1978 sandwiched between two normal 1978.

[MintErrors]

In my opinion, the planchets may have been rolled too thin. With the cent the only copper/bronze coin in active denomination, it can't be on a wrong planchet from the USA.

The US Mint did make coins for other countries. I do not recall the last year they did this.

There is a 60+ page report that lists a lot of countries that the US Mints made either planchets or coins for. So the first thing is to find a foriegn coin that was minted with the same year and the correct mint as well. So it would be 1978, Philadelphia mint. Then go through the list trying to find a copper/bronze coin or planchet that weighs very close to what your coins weigh.

It's probably a long shot, as it's more common to have a rolled thin planchet than a a Lincoln cent struck on a foriegn planchet.

Here is the link to the PDF file

https://www.minterrornews.com/news-5..._the_mint.html

[TR137]

Its far easier to just use the numista.com search, you can specify a range of years like 1977-1979, a range of weights like 2.2-2.8 (g) and the mint and it will show all the US and foreign coins that made that fit those criteria.

Looks like its a planchet intended for Liberia. I don't know why Numista says its brass (vs bronze for our penny) but lists both as 95% copper and 5% zinc.

https://en.numista.com/catalogue/pieces4769.html

[Vidroy Alkirk]

Thank you all for the helpful comments and resources. Given the uniformity of these 3 thin cents, and knowing that foreign-use planchets were available, my theory until convinced otherwise is that they were intentionally made as a trial rather than error. My method of coin-roll hunting involves frequent use of a scale. Without checking weights, I would have easily missed them. In fact, I missed the first one but when weighing the roll of fifty, I suspected a Zincoln was misplaced within the roll of all coppers. Much to my surprise, it turned out to be a thin 1978. About 5 years later, I found another and then a third again another year later. I suspect that more could be found if collectors weighed their 1978 Lincoln cents. The price of copper spiked at $1.40/lb in 1974 and the aluminum 1974 Lincoln cent was made as a trial. Copper spiked again at $1.40/lb in 1978. Then 1982 ... year of the Zincolns. My scale doesn't detect hundredths of a gram, so they could be 2.59 g and still read as 2.5 g.