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Explore 2 published pages tagged with Copper Oxidation, grouped automatically from article text, entity focus, and recurring topical signals.
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numismatics
The U.S. one-cent coin, commonly called the penny, appears brown in everyday circulation because it is made mostly of zinc with a thin copper coating. Modern Lincoln cents minte...
Open articlecoins-and-collectibles
The penny turns brown primarily because copper reacts with oxygen and other substances in the air, creating copper oxides and other compounds that dull its bright metallic luste...
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