The unique British Guiana 1c magenta, the world’s rarest stamp, will come up for auction on June 17. Its pre-sale estimate is $10-20 million.

The rarity, which has not been seen in public since 1986, will be auctioned by Sotheby’s in New York and will visit London and Hong Kong before the sale.

It had belonged to multimillionaire John du Pont and languished in a bank vault after his conviction in 1997 for killing a wrestler at his family mansion.

The 1856 British Guiana issue was locally printed when a shipment from Waterlow’s in London did not arrive, and there is one surviving example of the 1c.

In 1873, L. Vernon Vaughan, a 12-year-old Scottish schoolboy living with his family in British Guiana, found the stamp among a group of family papers bearing many British Guiana issues. He later sold the stamp to another local collector in British Guiana, for several shillings.

The 1c was bought by the famous Count Philippe von Ferrary in 1878. After World War I, France seized his collection, which had been donated to the Postmuseum in Berlin, as part of the war reparations due from Germany, and sold the stamp in 1922 as one of a series of celebrated auctions from 1920–25.

It was bought by noted philatelist Arthur Hind, for its first auction-record price of $35,000, followed by Australian engineer Frederick T. Small; then a consortium headed by Irwin Weinberg; and then by du Pont, who was heir to a chemical company fortune and an avid collector. Du Pont paid $935,000 for the stamp in a 1980 auction, and exhibited it several times. He died in prison in 2010.

The current auction record for a single stamp is 2,875,000 Swiss francs (approximately US$2.2 million), set by the Swedish treskilling yellow in 1996.