The Civil War Effect on Coins of the United States:
Wars have their effects, and here is how the Civil War deeply affected our coinage:
The Cent: Small cents had only been struck since 1857, and they were made of thick planchets with the alloy of 88% Copper and 12% Nickel. The nickel gave the coin a whitening effect, so people often called them 'Nickels,' as modern day nickels weren't struck yet. Because of the urgent need of nickel in the war, cents were changed to a thinner planchet and were struck in 95% Copper and 5% Tin and Zinc. The new bronze coin was continued until 1982, when it was changed to zinc, but that's another story.
Along with the modified alloy of the cent, a new bronze two-cent piece was minted; the two-cent piece had the same alloy as the cent and was exactly twice the weight.
In 1851, a tiny three-cent piece was made, the coin was even smaller than a half dime, and was made out of silver. Wars drive the price up on anything, including the cost of minting coins. Because of this, mintages of three-cent pieces dropped from a few hundred thousand per year to 20,000, and this kept dropping to 1,000 in 1872 and 600 proofs in 1873. Also, in 1865, a new, nickel three cent piece was begun, this coin was the exact same size as a silver dime.
Before the Civil war, several million half dimes were minted in Philadelphia, but it dropped to 118,000 in 1863. The half dime did recover, and passed a million in the years of 1871-1873, but was not minted afterward. It was not minted anymore for the same reason as the silver three-cent piece: A new, nickel half-dime took it place in 1866. Nickel Half-Dimes are not called half-dimes anymore, they are now called 'Nickels.'
In 1853, over 12,000,000 dimes were minted in Philadelphia, but only 1,883,000 were in 1861, and in 1867, as few as 6,000 were minted. It is very rare for dimes of this era not to have a mintmark, for San Francisco minted plenty during this era, as it was not as effected as Philadelphia was, being 3,000 miles away from the war.
Other coins dropped to one-third of their normal mintages, but recovered again.