Half Dimes

The half dime, or half disme, was a silver coin, valued at five cents, formerly minted in the United States.

Some numismatists consider the denomination to be the first business strike coin minted by the United States Mint under the Coinage Act of 1792, with production beginning on or about July 1792. However, others consider the 1792 half disme to be nothing more than a pattern coin, or "test piece", and this matter continues to be subject to debate.[1][2]

These coins were much smaller than dimes in diameter and thickness, appearing to be "half dimes". In the 1860s, powerful interests promoting the use of nickel as a metal for use in coinage successfully lobbied for the creation of new three and five cent coins, which would be made of a copper-nickel alloy; production of such coins began in 1865 and 1866, respectively. The introduction of the copper-nickel three and five-cent pieces made the silver coins of the same denomination redundant, and both silver denominations were discontinued in 1873.  Wikipedia