This coin was worth half a dollar when it was made in 1838. Now, it's worth an estimated half a million.
The specific coin being auctioned is called the Cox Specimen, which last changed hands in the 1980s, according to the auction house. It features a woman wearing a band that reads "Liberty" on one face, and the national symbol of the bald eagle on the other.
A 125-year-old dime just sold for $1.32 million
It was created at the New Orleans Mint, which opened in 1838 with the purpose of creating gold and silver coins. The coins created there are stamped with the letter "O," representative of the city's name, to distinguish it from coins made at other mints.
At the time, lots of silver coins were being imported into the United States from other countries like Mexico -- but silver coins from Latin America had an "uneven quality," said the auction house.
Converting them into silver half dollars would then turn these uneven coins into ones that were "fit for banking and commerce."
However, the mint ended up producing very few of these half dollars. The spread of yellow fever that year closed the mint for months, and technical issues halted progress -- making the existing few 1838-O half dollar coins highly coveted by modern collectors.
Rare 1943 copper coin fetches a pretty penny in auction: $204,000
One of the most enthusiastic collectors was a man named "Colonel" E.H.R. Green, who once owned six of the half dollar coins, including the Cox Specimen, according to the statement. The Cox Specimen was bought and sold by several other dealers before finding its way to the auction house.sonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
The other eight coins are either owned by dealers or are on display -- one of the coins is currently part of the National Numismatic Collection in the Smithsonian Institution in Washington, DC.
Incredibly rare US bank bills set to sell for $8 million at auction
Even if the coin sells for half a million dollars, it won't be the most expensive coin of its type.
Another 1838-O half dollar coin sold for $763,750 in 2014. Most recently, one fetched $444,000 at a Florida auction last January.
The difference in selling price depends on market forces as well as the grade and "eye appeal" of the individual coin, Vicken Yegparian, Vice President of Numismatics at the auction house, told CNN in an e-mail. For instance, the Cox Specimen has highly reflective surfaces with sharp and distinct features.
Stack's Bowers Galleries has made headlines for astronomical sales before -- a famous silver coin dated 1794 sold for over $10 million in 2013, setting the world