A penny minted at the San Francisco Mint in 1969 may be worth up to $600,000 due to what is referred to as a "doubled die obverse" mistake made during the minting process.

Stack's Bowers Galleries says a doubled die happens when a coin die gets a misaligned secondary impression from a hub during manufacturing and results in the design appearing doubled.

According to Stack's Bowers Galleries, the 1969-S Lincoln Memorial Cent Doubled Die Obverse "is an extremely desirable variety, having an estimated population of 50 to 60 pieces based on combined certification service statistics." What they're saying: Online precious metals e-commerce company SD Bullion calls the coin "The most famous error coin from the Lincoln penny is the 1969-S Doubled Die Error, Lincoln Penny, with prices ranging from $31,500 to $605,000." What you can do: If you come across what you think is a rare and valuable coin, you should locate a reputable coin dealer to evaluate the coin.