Composition25% nickel 75% copper "War Nickels" (mid-1942 to 1945): 56% copper 35% silver 9% manganese. 1.750 g 0.05626 troy oz, Jefferson War Nickels weigh exactly 5 gramsmodern Jefferson Nickel, it weighs 5 grams (0.176 ounces). It has a diameter 21.21 millimeters and it's composed of 75% copper and 25% nickel. Jefferson Nickel HistoryThe Jefferson Nickel was first struck by the U.S. Mint in 1938 and was a replacement for the buffalo nickel. This nickel was used during wartime, from the years 1942-1945. During this time, the Jefferson Nickel was minted with silver in order to preserve nickel for the war effort. When the U.S. Mint began production of the Jefferson Nickel, the coin was produced at three separate facilities: Philadelphia, Denver and San Francisco. More than 30 million Jefferson Nickels were struck in 1938 and they were released into circulation on November 15th of that year.According to some accounts, the Jefferson Nickel was widely hoarded when it was first released. It is said that the coin was not widely seen in circulation until 1940, almost two years after it was first produced.While the Jefferson Nickel has been produced with some different designs over the years, this coin remains a classic U.S. Mint circulation coin. Jefferson Nickels remain quite popular in modern times and are still produced by the U.S. Mint today.