Aluminum planchets were onceconsidered an alternative tocopper for cent production bythe U.S. Mint. Many collectors mayremember the 1.5 million 1974 Lincolncents that were struck in aluminum.The entire production wasrejected and all coins were recalled.One specimen exists legally andresides at the Smithsonian Institute.

A second specimen, known as theToven specimen, is detailed in a storywritten in July 2005 by the late AlanHerbert for Numismatic News.Slabbed by ICG, Herbert suggeststhat it is likely worth several milliondollars, if not more.

Many mints around the world strikecoins using aluminum planchets. It isalways exciting to encounter errorsstruck on a wrong planchet and thisarticle focuses on several havingbeen struck on aluminum.

The first error is a 50 pence fromGreat Britain. A normal 50 pencefrom this time period is seven sidedand weighs 8.0 grams. In 2007 Icame upon this 50 pence struck on ascalloped, 12-point aluminum blankweighing 0.80 of a gram. After sometidy research I found a likely match.I believe this blank was intended fora 1c coin from Belize. A normal 1cfrom Belize has a scalloped, 12-pointperimeter and has a specificationweight of 0.80 of a gram, an exactmatch for the weight of this errorcoin.

The second error carries the design ofa 2006 5 pence from Great Britain.This particular design began productionin 1995 and continues to the presentday. A normal 5 pence weighs3.25 grams. This wrong plancheterror weighs 0.70 of a gram and isstruck on a circular aluminum disc. Ihave yet to determine which countrythis aluminum planchet was intendedfor.

For more information on The Combined Organizations ofNumismatic Error Collectors ofAmerica (CONECA),, see:http://conecaonline.org/