Coin World just broke a story that another of the 1982-D Lincoln cent small date transitional off-metals have been found, bringing the known total to (2) examples. The new find is certified as NGC AU58, and is the same grade as the other known example, which was an AU58. The previously unique 1982-D sold for $18,800 in a Stacks auction in the summer of 2017. This new example was submitted, according to the Coin World article, by a major auction house, and so will likely be going to auction as well. Here is a link to the Coin World article: https://www.coinworld.com/news/us-coins/2019/02/ngc-confirms-second-bronze-1982-d-small-date-cent.html
The error occurs when there is a change in the metal content of a coin type. Leftover planchets from the earlier metal (in this case a 3.1 gram copper cent planchet) are accidentaly fed into a press striking the next generation of coins (in this case 2.5 gram zinc cent planchets), creating a coin with the prior years metal on the next metal year's coins. These are always rare, and there are no "common" transitional off-metals known on U.S. coins. Most have less than a dozen examples known for any particular metal change, and we aren't aware of any transitional off-metal with more than about 25 known examples.
There are other known examples of transitional 1982/1983 cents, including:
-One or two 1983-D transitional copper cents.
-Probably seven or eight 1983 transitional copper cents.
All examples of transitional 1982 or 1983 copper cents typically sell for $10,000 to in excess of $20,000, depending on the grade, and if they are in an NGC or PCGS holder. In our opinion, it is important to buy them in one of these two 3rd party holders since some of the other grading services aren't as careful with making sure the coin's are actually transitional off-metals asopposed to simply being struck on overweight zinc cent planchets. For example, sometimes you have have a heavy zinc cent in 1983, which coin might weigh 3 grams. This would be within tolerance for a copper transitional 1983 cent. In such a case, the only way to be 100% sure the coin is copper and not simply a heavy zinc cent, is to do a non-destructive metal anaylsis, which will give the composition of the planchet, and thereby give an accurate attribution of the error.
These are all being found in circulation (that we are aware of), making them a ripe area for Cherrypicker's to search for examples in their pocket change. Of course, the odds of finding them are very slim, but with enough searching, people are finding them. You would need to use a scale to identify them, since they are very similar in appearance to a normal "zinc" cent. A copper cent weighs 3.1 grams, whereas a zinc cent weighs 2.5 grams, making the difference in weight an easy diagnostic for the transitional off-metals.
If you own one of these interesting coins, you have a rarity, and a coin which transitions the change in metals for the Lincoln cent. We have sold a small number of these, and they are always an interesting error to handle.
Image: Courtesy of Heritage Auctions. (1983 Lincoln cent transitional off-metal.)