An important MS65-graded US 1920-S double eagle has sold for a record $517,000 at Heritage Auctions.

It was the lead lot of a sale of US coins in New York that closed on November 2.

The 1920-S double eagle is one of the rarest in its series

The 1920-S is one of the rarest dates in the series at gem standard, with the present lot one of only three at this level.

While it's the third finest known, it's now the most valuable - having exceeded the $264,500 paid for another MS65 graded specimen in 2007.

Heritage explained prior to the sale: "The bulk of the 558,000-coin mintage, after assay, was presumably kept in storage until the gold melting of the 1930s consumed the vast coin reserves in federal vaults…

"In recent decades, low-end examples of the date are actively traded, but the top-grade Gems remain incredibly rare."

An XF-40 1870-S seated dollar achieved $434,750.

The coin is one of nine produced in secret to celebrate the opening of the San Francisco branch mint that same year.

There is no mention of the coin in the mint's records. It's thought to have been commissioned by SF Mint superintendent AH LaGrange to be placed under the cornerstones of the building as a good luck token.

He is believed to have borrowed the plates from Carson City, as he had a close friendship with the superintendent there.