An MS61-graded 1866-S $20 "No Motto" double eagle will star in a November 1 sale of US coins at Heritage Auctions in New York.
Bidding will start at $235,000.
In the aftermath of the civil war, a campaign was successfully waged to have the motto "In God We Trust" added to US coinage.
The plan was implemented in 1865, but the dies did not reach San Francisco until March 1866 - meaning around 120,000 double eagles minted there earlier in the year were issued without the phrase.
The majority were destroyed in President Franklin Roosevelt's 1933 gold recall.
Heritage explains: "Today, approximately 200 examples of the 1866-S No Motto double eagle can be accounted for, making the issue scarce-to-rare in all grades and conditions…
"This coin exhibits well-detailed design elements, with a better-than-average strike, and pleasing honey-gold surfaces, with a few hints of rose…
"We expect intense competition when this classic gold rarity is offered, as a comparable specimen may not become available for years."
An MS66-graded 1907 $20 high relief wire rim is expected to exceed $71,675.
Designed by Augustus Saint Gaudens, it is considered the most beautiful US coin ever issued. An extra high-relief specimen sold for $2.9m in 2005.
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