An MS65-graded US 1920-S double eagle will cross the block at Heritage Auctions in New York later this month.
The lot is one of the highlights of a sale of US coins that runs from October 31-November 2. It's expected to sell for in excess of $260,000.
The 1920-S is among the rarest dates in the series at gem level, exceeded only by the 1921 and 1927-D.
As the auction house explains: "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."
The present lot is the third finest specimen known and the best of the three coins registered at this grade. Another MS65 example achieved $264,500 in a 2007 sale.
An 1870-S seated dollar is valued at more than $220,000.
The coin is thought to have been produced secretly to commemorate the opening of the San Francisco branch mint.
It's the sixth best of nine confirmed examples at all grades and last sold for $805,000 at Heritage in 2015.
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