Twenty cent coins
were only struck for circulation during 1875 and 1876. The
coin was about the same size and design of the Quarter Dollar,
so people were always confused about the worth of the coin.
It was too hard to tell the difference between a quarter and
a twenty-cent coin. In 1877 and 1878, the twenty cent coin
was available as a proof (a newly-minted coin that is not
circulated). The government stopped minting the twenty cent
coin in 1878.