NGC Certifies Unique
Wartime Discovery
2.5 Gram Bronze Cent
Struck at the San Francisco Mint

This is a fascinating 1942-S Lincoln Cent that was struck on a 2.5 gram bronze planchet with a composition of 95% copper, 4% zinc and 1% tin. After examining this unique mint error and consulting with many experts on mint errors, patterns and die trials, the consensus is that it was struck on a 1942 Curacao cent planchet that had been coated or plated with zinc before being struck.

Planchets for the 1942 Curacao cent were produced by the U.S. Mint in Philadelphia and have the exact same specifications as this 1942-S cent; 2.5 grams in weight, a diameter of 19mm and a composition of 95% copper, 4% zinc and 1% tin. However, Curacao cents were never struck in San Francisco!

Mint Error News has a 69 page report of coins struck by the U.S. Mint for foreign countries. It is the most comprehensive report available anywhere. Page 9 details the coins that were struck for Curacao including the 2.5 gram bronze cent planchet. Click here for a PDF of the 69 page report.

This unique new discovery has a partial zinc appearance on the obverse and reverse as well as a zinc band on the edge.



The U.S. Mint in Philadelphia experimented extensively with zinc and copper planchets during World War II. These experiments have been outlined in Roger Burdette's book United States Pattern & Experimental Pieces of WW-II. Test planchets in various compositions were produced, as well as many experimental surfaces such as plating and coating.

It is common procedure for pattern experts including NGC and Roger Burdette as well as the authors and researchers of the Judd reference book United States Pattern Coins, to classify coating and plating in their determination.

Dave Camire and NGC authenticated and certified the Philadelphia Collection which had many cents and planchets that were coated and plated at the Philadelphia Mint. They also authenticated and certified many 1942 and 1943 Lincoln cents and planchets that were either coated or plated.

As amazing as it seems, it appears that this Curacao cent planchet was either coated or plated with zinc in the experiments during the transition of U.S. cents from bronze planchets to zinc-coated steel planchets.

If the planchet was intentionally plated or coated with zinc as part of the experiments then this would be classified as a test piece. If the planchet was accidentally mixed with U.S. cent planchets that were being experimented on, then it is a mint error. Subsequently, it somehow was transferred to the San Francisco Mint and struck by U.S. cent dies in 1942.

Although accidentally mixing planchets between U.S. Mint branches seems unlikely, it has occurred several times between the U.S. Mints in Denver and in San Francisco. There are 1974 Denver silver Ike Dollars struck on planchets produced in San Francisco. And there are also 1977 Denver silver Kennedy Half Dollars struck on planchets produced in San Francisco.

Although there is no absolute proof that this is exactly what occurred, nor is there any documentation, the most logical explanation to describe the chain of events of this unique 1942-S cent is intriguing and enigmatic. A Philadelphia Mint produced Curacao planchet was likely coated or plated when Philadelphia experimented with copper and zinc planchets and was subsequently struck in San Francisco by U.S. Cent dies.

For comparison and to provide similar information relative to 1942 U.S. Lincoln cents that were patterns, test pieces or mint errors, here are two excellent examples:

I recently handled the unique 1942 Philadelphia Mint Lincoln cent struck on an aluminum planchet in proof. Clearly it was a pattern and test piece experimenting with a different composition and alternative to producing copper cents in 1943, due to the copper shortage during World War II. This unique aluminum cent has traded several times, once at $300,000.

Another unique 1942 Lincoln cent experimental off-metal struck at the Philadelphia Mint was 95% tin and 5% zinc, realizing $86,250 in a Stack's auction in 1996 (lot #4253). In comparison, in 1996, copper 1943 Lincoln cents were $30,000 - $50,000. Today they are $200,000 - $350,000.

This unique 1942-S cent, most likely struck on a 1942 Curacao cent planchet from the Philadelphia Mint, coated or plated with zinc and then struck in San Francisco by U.S. cent dies, will remain an enigmatic discovery. It belongs in a world-class collection of Lincoln cents, major mint errors or unique numismatic rarities.

Click here to view the Mint Error News exclusive article Foreigners in the Mint and a 69 page report of coins struck by the U.S. Mint for foreign countries. It is the most comprehensive report available anywhere.

Off-Metal Errors are featured in the NLG award
winning book, World's Greatest Mint Errors.