1970-S Proof Washington Quarter
Struck on a Silver Barber Quarter
1 of 2 Known


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.

A very small group of Proof errors recently came from a collection that was auctioned by the State of California. 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 it has been dispersed since the sale.

Proof Washington Quarters struck in 1970 by the San Francisco Mint were clad. This 1970-S Proof Quarter was over-struck on a Silver Barber Quarter and is one of two known. This mint error was originally discovered in group of San Francisco Proof Errors that was auctioned by the State of California. There is some detail on both sides showing the design of the Barber Quarter. This is one of the most famous U.S. Proof Major Mint Error ever released from the San Francisco Mint.



These famous and enigmatic Washington Quarters from the San Francisco Mint struck in Proof, over a U.S. Silver Barber Quarter (1892-1916) and over a 1941 Canada Silver Quarter. These were both featured in a TV interview I did with Fox News. These fascinating errors went "viral" and were featured in USA Today, London's Daily Mail, AP News, Coin Week, New York Post, Newsmax, NBC News, Numismatic News, Time Magazine and on Maria Bartiromo's TV show.


Featured on the cover of Mint Error News Magazine Issue 37



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



The Mint Error News website has a 69 page report of coins struck by the U.S. Mint for foreign countries. It is the most comprehensive report available anywhere. Click here for a pdf of the 69 page report.


Click here for a pdf of the 69 page report.