This is the only known Standing Liberty Quarter struck on a foreign planchet for the entire series. Standing Liberty Quarter Off-Metals are so rare that there are only a handful known struck on any other planchet. This unique off-metal is a very recent discovery and was unknown to the numismatic community and not listed in any reference book or catalog.
It was struck on a Peru 20 Centavos planchet with a weight of 6.9 grams, a diameter of 24mm and a composition of 75% copper and 25% nickel.
In the reference Domestic and Foreign Coins Manufactured by Mints of the United States, 1793-1976 published by the U.S. Treasury, we find that in 1920, the Philadelphia mint struck 20 centavos pieces for Peru that were made of 75% copper, 25% nickel with a diameter of 24mm and a gross weight of 7 grams. This Standing Liberty Quarter off-metal has a copper-nickel look instead of silver, is full size and is considerably thicker than a silver quarter blank.
This is one of the most incredible and rare major mint errors that I've ever had the pleasure of offering for sale. It is an extreme rarity and would be the centerpiece of any mint error or Standing Liberty Quarter collection.