The Civil War

Five-cent pieces had been struck by the United States Mint since 1792; they were the first coins struck by Mint authorities.[1] These half dimes (originally spelled "half dismes"), were struck in silver. The alloy used was originally .892 silver with the remainder copper; the silver portion was increased, beginning in 1837, to .900.[2]
The Civil War caused most American coins to vanish from circulation, with the gap filled by such means as merchant tokens, encased postage stamps, and United States fractional currency, issued in denomination as low as three cents. Although specie (gold or silver coins) was hoarded or exported, the copper-nickel cent, then the only base metal denomination being struck, also vanished.[3] In 1864, Congress began the process of restoring coins to circulation by abolishing the three-cent note and authorizing bronze cents and two-cent pieces, with low intrinsic values, to be struck.[4] These new coins initially proved popular, though the two-cent piece soon faded from circulation. On March 3, 1865, Congress passed legislation authorizing the Mint to strike three-cent pieces of 75% copper and 25% nickel.[4]