The first known example of a 1974-D aluminum cent will go on the auction block during the Central States Numismatic Society convention April 23-27 in Schaumburg, Ill., in a Signature Sale conducted by Heritage Auctions.

"This is an amazing discovery and we estimate the 1974-D aluminum cent will bring a quarter million dollars or more," said Todd Imhof, Heritage Auctions executive vice president.

Long rumored to exist in private hands, the example going on sale traces back to Harry Edmond Lawrence, deputy superintendent of the Denver Mint.

The rarity passed to his son after he died in 1980 and Heritage relates that he did not know what he had.

Last September Randy Lawrence arranged to sell the coin and others he had inherited to Michael McConnell of La Jolla Coin Shop in California.

Heritage quotes McConnell as saying, "I first thought the 1974-D cent was struck on a planchet intended for a foreign country, and I purchased it as such."

He called Armen Vartian, the legal counsel of the Professional Numismatists Guild, who has his office in Manhattan Beach, Calif. Vartian called error specialist Fred Weinberg of Encino.

The coin was submitted to the Professional Coin Grading Service by McConnell as arranged by Vartian.

PCGS calls the pattern genuine and graded it MS-63.

"There's been speculation about the existence of 1974-D aluminum cents for decades. Now, there's a confirmed coin, and a portion of the proceeds from its sale will be used by the sellers to help the homeless," Imhof said.

Randy Lawrence said the aluminum cent and other coins he inherited had been kept in a plastic sandwich bag by his father.

"I didn't know what the coins were. My father sometimes received coins as gifts during his government service, and I kept them in that same plastic bag in a desk drawer for 33 years," said Randy Lawrence.

Aluminum cents were mass produced in 1974 on the expectation that Congress would approve the composition for use in the cent. Examples were given out to elected officials as they deliberated. Congress did not approve the composition and the Mint requested the patterns be returned. Most were, but an estimate five to 14 were not.

According to a Feb. 21, 1976 story in Numismatic News, the United States government closed its investigation of any missing 1974 aluminum cents by February 1976 having found, in the government's own words "no evidence of criminal intent" by anyone possessing any of the coins.

To read the complete article, see:Heritage Schedules Aluminum Cent Sale(numismaster.com/ta/numis/Article.jsp?ad=article&ArticleId=27601&et_mid=658552&rid=238176646)