A 1942 1c Lincoln cent minted in an experimental aluminium alloy is offered with a starting bid of $16,000 at Heritage Auctions.
The lot will lead the April 23-27 US Coins Signature Auction in Chicago.
A series of pattern cents were struck in a variety of metals and alloys in 1942 in an attempt to create a more hardwearing and durable coinage - although the number produced is unknown.
Heritage commented: "This is an extraordinary piece. Each side is bright, and there are no signs of oxidation. The fields have a pronounced mirrorlike appearance, and there are light flow lines evident on the reverse.
"The obverse is slightly convex, and the reverse slightly concave. This is essentially a perfect coin with no observable marks on either side."
An 1889-CC silver dollar is valued in excess of $11,000.
Due to the poor state of the equipment within the Carson City Mint, which had been abandoned since 1885, only 350,000 silver dollars were produced in 1889.
The proof-like example offered in the sale is graded MS63 and displays clean and unmarked surfaces. While a large number of the issue are available in this condition (around 48%), its popularity as a key rarity ensures that examples are always in demand.
In 2012, a comparable specimen made $38,187 at Heritage in Philadelphia.
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