This tiny silver coin is also known as a "Trime" or a "Fish-scale". The odd denomination is tied to the Postal rates at the time, which were also the justification for the Gold Three-Dollar Coin. Beginning in 1865, this type overlapped with the Nickel Three Cent Coins and the production of the Trimes decreased gradually until the type was ended in 1873.
Three sub-types exist of the silver Three Cents. Type 1, issued from 1851 to 1853, shows the obverse star with a single outline. After 1853 two extra outlines were added to the star to signify a reduction in weight, resulting in the Type 2 version that lasted until 1858. In 1859, one of the extra outlines was dropped, creating the third and final sub-type, the Type 3 version.
1851 was the only year that a mint mark is found on a Three Cents Silver Coin, all others don't have a mint mark which signifies them as struck at the Philadelphia Mint. The 1851-O was struck at the New Orleans Mint and the O Mint Mark is found inside the opening of the C shape.