1971-S Proof Eisenhower Dollar
Overstruck on a Bronze
San Francisco Assay Office Medal



This unique and amazing 1971-S Proof Eisenhower Dollar was overstruck on a 17.1g bronze San Francisco Assay Office Medal. Although there are three known Eisenhower Dollars struck on bronze planchets (two in mint state, one in proof) this is the only one known that was overstruck on a struck bronze medal.

Although the San Francisco Assay Office Medal weighs 17.1 grams and has a smaller diameter than an Eisenhower Dollar, the pressure of the strike from the proof dies expanded the diameter to the size of an Eisenhower Dollar. It is in superb gem proof red condition and shows considerable detail from the design of the understrike. An absolutely phenomenal and world-class major mint error!

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. This Proof Eisenhower Dollar overstruck on a Bronze Medal was intentionally struck.




NGC Certificate Verification

The American Numismatic Association (ANA) is a non-profit educational organization dedicated to coin collectors. The ANA received a federal charter from the U.S. Congress in 1912. It features the Money Museum which exhibits collections in its galleries. Included is a collection of Eisenhower Dollar mint errors from the famous Dr. Berry Collection of proof and mint state error coins. In this collection are two mint state 1971-D Eisenhower Dollars struck on copper planchets intended for U.S. Mint Medals. They are included in the ANA Museum Inventory List.

ANA Museum Inventory

ANA Museum Inventory


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.

Rare Eisenhower dollars are featured in a Mint Error News article:

The Rarest Eisenhower Dollars Known


Featured on the cover of Mint Error News Magazine Issue 62:


Proof errors are featured in my NLG Award winning book, World's Greatest Mint Errors.