Last pennies minted in the US sell for over $16 million

(CNN) - A few historic pieces of copper turned out to be worth much more than their weight in gold.

The last pennies to ever be minted in the U.S. just sold for more than $16 million, according to auction company Stack’s Bowers Galleries in California.

Among the items up for grabs were sets of three coins, including a 24-karat gold penny from the U.S. Mint in Philadelphia.

More than 230 of these packages were sold for an average of $7,200 each, with one set going for $800,000.

The auction took place exactly a month after the U.S. Mint in Philadelphia stopped minting the penny.

The Trump Administration ordered the U.S. Mint to stop making pennies due to cost inefficiency.