San Diego (KSWB) -- A San Diego man and an antique shop owner have entered a legal battle with the U.S. government over a penny.


When Randy Lawrence brought his rare penny to the La Jolla Coin Shop he was pleasantly surprised. The coin is one of a kind; a Denver minted, aluminum penny, estimated to be worth about $250,000.


"It was kind of a treasure in the attic story," he said. "I never thought it would have this kind of a value."


Coin experts said the coin was a product of a failed attempt by the U.S. Mint to replace copper pennies with aluminum ones in the 70s- all the coins were supposed to be destroyed.


Lawrence, a real-estate agent, said he doesn't know exactly how his father, who worked at the U.S. Mint in Denver for years, ended up with one of the aluminum pennies.


Lawrence and coin shop owner Michael McConnell planned to auction it at a big coin convention in Chicago later this month, but that plan had to be put on hold.


"We got the letter from the government wanting the coin back," said Lawrence.


The feds said the aluminum penny was never issued as legal currency and therefore it is government property.


Lawrence and McConnell are taking their case to a federal judge claiming they are the rightful owners of this pretty penny.