1977-S Proof Jefferson Nickel
Overstruck on 1977-S Roosevelt Dime

1 of 4 Known


This is the only double denomination
of the four known showing two dates.

A group of modern United States proof errors surfaced recently from a 40 year old collection. Double denominations (U.S. coins struck on smaller denomination coins) were unknown. Four proof Jefferson nickels overstruck on struck dimes were in this collection.

On this double denomination, the design of the dime is clearly visible on both the obverse and reverse upon close examination. It is a flip-over double denomination. The 1977 dime date is clearly visible in the field to the right of Roosevelt's neck. Roosevelt's profile is visible under both sides of the memorial. Other details from the Roosevelt dime reverse design are visible under the Jefferson obverse design. This is the only double denomination of the four known showing two dates.

Recently in a Heritage auction, a similar 1977-S Proof Jefferson Nickel struck on a Roosevelt Dime, but without a visible date from the dime design, sold for $9,300.

Proof coins are struck by technicians who hand feed the blanks into special presses. They are produced, examined and packaged using extreme quality control. It is very unusual to find major proof errors. A few broadstrikes, off-centers, double strikes (in collar) and off-metals have been known to be found in sealed proof sets. Proof errors are aggressively sought after by many error collectors.

Roosevelt's portrait and the 1977-S
date are visible from the understrike:


The olive branch from the dime reverse
design is visible from the understrike:






Intentional Errors

One of the most controversial categories of U.S. coins are mint errors. Many dealers and collectors, as well as coin auction houses, buy, sell, trade and auction many rare, exotic and unique major mint errors. Obviously, some of these defy logic and were intentionally created and taken out of the Mint.

In the early 2000's, a group of several hundred U.S. error coins were found in a safe-deposit box. Fred Weinberg purchased this group which included coins struck for proof sets and also coins struck for circulation. This group was auctioned by the California State Controller's Office of Unclaimed Property. The U.S. Secret Service inspected and released this collection to the State of California determining that it was legal to own. The State of California then auctioned the collection and the rest is history.

Another example of U.S. error coins escaping the Mint occurred in the 1970's. A hoard of proof error coins were smuggled out of the San Francisco Mint inside the oil pans of forklifts that were being serviced outside of the Mint. This topic was discussed in the June 6, 2022 Issue of Coin World, which covered Fred Weinberg's account of this story. The Coin World Managing Editor concluded:
Obviously, the marketplace accepts these coins, and some collectors are happy paying thousands of dollars for coins that show every indication of having been created through illegal means.

In Episode 11 of the PCGS video series Slab Lab, Seth Chandler interviews Fred Weinberg. In part 2 of the interview, Fred explains in detail why mint errors that are decades old are not recovered by the U.S. Mint. Fred's recollection of conversations in his office with the Chief of the U.S. Mint Police are extremely insightful and explain why the Mint doesn't attempt to recover error coins from decades ago.

Proof Errors are featured in chapter 21 of my
NLG Award winning book, World's Greatest Mint Errors: