CHICAGO - A torn envelope bearing a rare 90-cent Abraham Lincoln stamp from 1869 - a Maserati of sorts in stamp-collecting circles - is set for auction next month in New York City.

Philatelists had thought the "Ice House Cover," a 3 ¾ by 9-inch envelope mailed from a Boston ice importer to its icehouse in Calcutta, India, in 1873, was lost forever. Stolen from the home of an Indianapolis collector in 1967, the cover didn't resurface until 2006, when a couple showed up at a stamp-collecting shop in Norwood Park, Ill., and inquired about its value.

Charles Berg, owner of Stamp King, said he knew immediately the envelope was valuable. Once he learned it was "hot," Berg had an associate call the Chicago Police Department while the couple remained in the shop.

No charges were filed against the couple. Avid collectors of coins, antiques and stamps, they told investigators they likely either picked up the envelope at a garage sale or found it after cleaning the home of a deceased friend. The man said he had tossed it in the top drawer of a spare dresser a couple years back.

The FBI confiscated the envelope. Two years later, a judge returned the property to the estate of the Indianapolis collector, J. David Baker.

On June 13, the Robert A. Siegel Auction Galleries will auction off the envelope on behalf of Baker's estate. Scott R. Trepel, president of Siegel, estimated "Ice House" would fetch at least $300,000.

"Predicting these things are very difficult," Trepel said. "For something to be stolen and lost for so many years, and then turn up - it's pretty remarkable."

(c) 2009, Chicago Tribune. Distributed by McClatchy-Tribune Information Services.