How can you tell if your 1943 Penny is the valuable bronze error? Try picking your coin up with a magnet. If your coin is attracted to the magnet, it is made of copper-plated steel (a fraud). If the magnet does not attract your coin, it may be made of bronze and you should have the coin authenticated to determine if it is the "real deal".
In 1943, the U.S. Mint began using steel blanks for the Cents in an effort to conserve copper for use in World War II. Over a billion "Steelies" (as they are known popularly) were struck by the three Mints combined in 1943; Philadelphia alone produced over 684,000,000 examples. However, a handful of rare 1943 Cents have been discovered struck in error on old-style, bronze blanks. Presumably, the error occurred when left-over bronze planchets were mixed with a batch of the new Steel planchets, went through the usual striking methods, then escaped into circulation, bypassing the quality control procedures at the Mint. Today, 1943 Cents on Bronze Planchets rank among the most desirable and valuable of all Mint Errors.
Approximately 10-12 examples are known 1943 Cents on Bronze Planchets. Here are pedigrees of four of them:
1. NGC MS-61 Red and Brown. Ex - Southern California collector - Allen Levy of Al's Coins (National City, CA) - Columbia Rarities Group, Inc. on November 10, 1999, sold for $85,000, ANACS MS-61 Red and Brown - Fullerton, California collector and vest-pocket dealer Steve Benson on December 22, 1999, sold for $102,500 - Fowler, California coin dealer Sarkis "Sam" Lukes, December 27, 1999, sold for $112,500 - Staten Island, NY stock broker. According to Lukes, there are 17 1943 Bronze Cents known (10 from Philadelphia, six from San Francisco, and one from Denver); this conflicts with another census that lists 12 from Philadelphia.
2. PCGS MS-61 Brown (illustrated above). Ex - found in circulation circa 1957 by 14-year old Marvin Beyer, who reportedly turned down an offer of $20,000 for the coin - Abe Kosoff's "A.N.A. Convention Sale - A Festival of Coins" Sale, 1958, Lot 2055 (where it was withdrawn prior to the sale) - Superior Galleries' "Pre-Long Beach Sale", October 1-3, 2000, Lot 4146, illustrated, ANACS MS-61, sold for $60,375.00 - Ira & Larry Goldberg Coins & Collectibles, Inc. "The Benson Collection, Part III", February 24-25, 2003, Lot 148, illustrated, now PCGS MS-61 Brown (#50035361), sold for $97,750.00
3. EF-40, obverse and reverse stains and corrosion (illustrated below). Medd Family (received in change) - Heritage Numismatic Auctions, Inc.'s 1999 ANA Signature Sale, August 11-13, 1999, Lot 5171, sold for $32,200.00, "XF-40".
4. New discovery. Purchased along with other off-metal 1943 and 1944 Lincoln Cents by Sarasota Coin and displayed at the 2000 F.U.N. Convention.
Sources and/or recommended reading:
"Beyers' 1943 Cent To Be Sold In Convention Sale", The Numismatic Scrapbook Magazine, page 933
"1943 Bronze Cent Sets Price Record" by Paul Gilkes, Coin World, January 10, 2000
Numismatic News, January 11, 2000
Sam Lukes, Letter to the Editor, Numismatic News, February 1, 2000