NEW YORK -- Three times in its long history, the 1-cent postage stamp from a 19th-century British colony in South America has broken the auction record for a single stamp.

Now, it's poised to become the world's most valuable stamp again.

Sotheby's predicts the 1856 British Guiana One-Cent Magenta will sell for between $10 million and $20 million when it's offered in New York on June 17.

"You're not going to find anything rarer than this," said Allen Kane, director of the Smithsonian National Postal Museum. "It's a stamp the world of collectors has been dying to see for a long time."

Measuring 1 inch-by-1 1/4 inches, the feather-light One-Cent Magenta hasn't been on public view since 1986. It is the only major stamp absent from the British Royal Family's private Royal Philatelic Collection.

An 1855 Swedish stamp, which sold for $2.3 million in 1996, currently holds the auction record for a single.

"This is the superstar of the stamp world," said David Redden, Sotheby's worldwide chairman of books and manuscripts, adding that the stamp will travel to London and Hong Kong before being sold.

The modest stamp's origin and current history is as intriguing as the estimated price is staggering.

The last owner was John E. du Pont, an heir to the du Pont chemical fortune. It's being sold by his estate.

Printed in black on magenta paper, it bears the image of a three-masted ship and the colony's motto, in Latin, "we give and expect in return." The stamp went into circulation after a shipment of stamps was delayed from London and the postmaster asked printers for the Royal Gazette newspaper in Georgetown in British Guiana to produce three stamps until the shipment arrived: A 1-cent magenta, a 4-cent magenta and a 4-cent blue.

To safeguard against forgery, the postmaster ordered that the stamps be initialed by a post office employee.

While multiple examples of the 4-cent stamps have survived, only the one tiny cent issue is known to exist today.

Its first owner was a 12-year-old Scottish boy living in South America who found it among family papers in 1873. He soon sold it for a few shillings to a local collector, Neil McKinnon.

McKinnon kept it for five years before selling it to a Liverpool dealer who recognized the unassuming stamp as highly uncommon. He paid 120 pounds for it and quickly resold it for 150 pounds to Count Philippe la Renotiere von Ferrary, one of the world's greatest stamp collectors.

Upon his death in 1917, the count bequeathed his stamp collection to the Postmuseum in Berlin. The collection was later seized by France as war reparations and sold off in a series of 14 auctions with the One-Cent Magenta bringing $35,000 in 1922 -- an auction record for a single stamp.

Arthur Hind, a textile magnate from Utica, N.Y., was the buyer. Upon Hind's death in 1933, the stamp was put into an auction with the rest of his collection but was withdrawn after his widow, who claimed it was left to her, brought a lawsuit.

Frederick Small, an Australian engineer living in Florida, purchased it from Hind's widow for $45,000 in 1940. Thirty years later, he consigned the stamp to a New York auction where it was purchased by an investment consortium for $280,000 -- another record.

The stamp set its third record in 1980 when it sold for $935,000 to du Pont.