A Rare Dime Just Sold for More Than Half a Million Dollars—Here's What Makes It So Special

If you have a collection of coins sitting around your home, you may want to double-check their value. Three sisters in Ohio just sold a rare dime for $506,250 during an online auction.

The mother and brother of the sisters (who wish to remain anonymous) purchased the coin in 1978 for $18,200. The coin sat in a bank vault for over 40 years until it was inherited by the sisters following their brother's death. The sisters shared with Newsweek that their family owned a dairy farm and kept the valuable coin for financial security. One of the sisters had never even seen the coin until last year.

The 1975 coin features a portrait of President Franklin D. Roosevelt and is part of a collection of proof dimes. The coin has an error that adds value to it: a missing S mint mark, which indicates where a coin was produced. It is one of two in the collection that contain this error.

“Mint marks hold the maker responsible for the quality of a coin,” according to the United States Mint. “When the U.S. used precious metals such as gold and silver to make circulating coins, a commission evaluated the metal compositions and quality of coins from each of the Mint facilities. The evaluations ensured that each facility produced coins to the correct specifications.”

According to the lot listing, the San Francisco Mint produced a "proof" set of over 2.8 million coins. Three years later collectors discovered that two of the dimes were missing the "S" mark. "This is a very exciting coin for our company to auction,” Ian Russell, president of GreatCollections said to Newsweek. "We’ve handled many trophy coins over the years, including two 1913 nickels and two 1804 silver dollars—but this is the first time for the 1975 no S proof dime."

The dime was displayed at a coin show in Tampa, Florida before being sold in an online auction on October 27, where it fetched more than half a million dollars.