There are two general kinds of three-cent U.S. coins. The first are the silver coins known as trimes among numismatists but called “fish scales” by mid-19th-century consumers due to their diminutive size. These were struck between 1851 and 1873. Three-cent nickel coins designed to replace the silver ones were minted between 1865 and 1889.

The introduction of trimes coincided with the lowering of postal rates from five cents to three. The coin was essentially conceived as a denomination to purchase this postage, which was important because the widely available copper large cents in circulation at the time were routinely refused by merchants, which made them understandably unpopular with the public. In addition, the majority of silver coins in circulation, foremost among them Seated Liberty quarters, were either being hoarded or melted for their bullion value, which was greater than their face value. Small trimes injected a much-needed supply of coinage into the economy.

The three-cent trime was designed by the U.S. Mint’s chief engraver, James Barton Longacre, who also created Flying Eagle and Indian Head cents, Shield nickels, and Liberty Head double eagles. There are three types of silver trimes, beginning with the Type I coins minted in Philadelphia and New Orleans in 1851, as well as those minted in Philadelphia in 1852 (the largest mintage) and 1853 (second largest). These feature a shield within a six-pointed star on the obverse and the Roman numeral III surrounded by a large “C” on the reverse. The composition of these Type I trimes is 75% silver and 25% copper...