A 1908 Australia 20 shilling postage due stamp, valued at $77,000, is among the top lots at Robert A Siegel's November 13-14 auction in New York.
It will highlight the Australian section of the Worldwide Stamps and Postal History sale.
The extreme rarity of the 1908 20 shilling postage due stamp results from the circumstances of its distribution.
It was issued to replace the former postage due series, which were printed in a uniform green and only featured the value in the border - making it difficult to distinguish shillings from pence.
In late 1908 or early 1909 the replacement postage dues, featuring a stroke after the 20 shilling, were distributed to just one area of Australia, New South Wales, with no announcement of the change.
They were not available to purchase in post offices, meaning the only way to purchase them was to send a letter of application to the deputy postmaster general in Sydney.
In July 1909, a new set of postage due stamps were issued, making these replacements obsolete.
Only one other used example of a used 20 shilling with stroke has ever been recorded, and features a similar cancel to this stamp. It dates to 1910.
A 1902 20 shilling postage due, one of the earlier examples that does not display a stroke, carries an estimate of $8,500. It features the original gum and, while lightly hinged, is of fine appearance.
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