Are there other coins that turned black like the U.S. zinc cents?
Zinc is not exactly a popular coinage metal for that very reason. Virtually every country that has issued zinc coinage – usually as a wartime expedient – has had the same or similar problems. Climates with high humidity and heat have more than their share of such problems. Historically, there was the so-called black money of 1300-1500. The debased silver quickly turned black in circulation. In some areas of Africa, especially Nigeria, the people referred to the copper and bronze coins as black money, and would accept only silver, nickel or aluminum coins. I have a quarter with two reverses [or obverses]. Is this a minting variety or a fake? It is an alteration, a so-called “novelty” coin, usually produced by hollowing out one coin and cutting down a second to fit inside, so that the joint is hidden on or along the rim on one side or the other, rather than on the edge. For the record, the U.S. Mint has never struck a two-“headed” or two-“tailed” coin that has reached circulation, except
