Blanchard

The smallest U.S. silver coin was created with two things in mind. First, in 1851, the intrinsic value of our silver coinage exceeded the face value, which led to the melting and hoarding of silver coins. This resulted in a shortage of small change. The three-cent silver, also called a "trime", was minted with an alloy of silver and copper that had less silver value than face value.

In addition, the denomination was tied to the cost of a postage stamp. The coin was favored for a while but it’s high copper content caused it to tarnish quickly and take on a filthy appearance. The trime was soon known derogatively as a "fish scale".