If the coin wasn't intended for circulation, then how do we know that this coin was made by a U.S. mint and not done as an art project in someone's home?
The eBay seller who sold the item, Mike Byers, is an expert in coins that were minted in error. He even wrote a book about them — World's Greatest Mint Errors.Since he's no amateur, he got the coin verified.
Beyers had the coin certified by the Numismatic Guaranty Corporation, a third-party certification group that verifies the authenticity of currency. They even have a registry dedicated to the coins they've verified, so now you have a fun activity to fill your afternoon.
The NGC verified that the coin was struck at the San Francisco Mint. It's unknown, however, how it ended up being printed over top of a Canadian quarter. If the boys down at the ol' mint were playing a joke, the joke's on them — it's worth $35,000 that they'll never see a penny of.
The coin was discovered in an unclaimed bank safety deposit box. The State of California gave the coins to the U.S. Secret Service, who authenticated the coins, and now you've learned about an important, but lesser-known function performed by the U.S. Secret Service. The State of California then auctioned them off.
The $35,000 coin still pales in comparison to the most expensive U.S. coin ever sold. The Flowing Hair dollar, the first dollar coin ever printed and circulated by the U.S. government, sold at auction for over $10 million.
Another U.S. coin that sold for millions is the Saint-Gaudens Double Eagle. Though nearly half a million of them were struck in 1933, they were never released and were melted into gold bars. Although one of these rare coins sold for $7.6 million, given that they were recalled, they were technically property of the U.S. mint. Since they're worth so much, the U.S. government has taken people to court over who rightfully owns the coins. One family took their coin to the Secret Service to have them verify it, and the Secret Service promptly confiscated it.
With all these expensive coins floating around, you might start looking at your loose change a little differently. And, if you ever need someone to verify that your 1967 dime is nothing special, remember you can always call the NGC. Or the Secret Service, though going to them is really flipping a coin.