A US 1858 5c brick red stamp with its original gum will lead the second part of the sale of the Irwin Weinberg collection at Robert A Siegel.
It looks set to sell for around $80,000 on November 9-11.
The colour of the 5c issue was changed from dark red to brick red in 1858 and discontinued two years later in 1860.
Only around 135,000 brick reds were printed. Of these few have survived and even fewer with their original gum.
The auction house commets: "After surveying dozens of classic United States sale catalogues, we found approximately twenty examples of Scott 27 with original gum, allowing for duplicate offerings and excluding the one known original-gum block.
"Of the stamps we counted, about half had perfs touching on two sides or were deeply cut into on one side. Almost two-thirds had stains or small faults.
"This sound example is a rarity among rarities."
Other highlights include a 1908 5c vertical coil in mint, never hinged condition. It's valued at around $12,000.
It's one of very few examples of this issue to display wide margins on both sides, as most are lopsided, making it a big ticket item for collectors.
The first part of the sale will feature an exceptional Inverted Jenny.
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