Various countries have produced coins that were specifically for use in foreign trade, some of which continue to be popular with coin collectors. Between 1873 and 1878, the United States Mint in Philadelphia, Pennsylvania produced a silver dollar coin known as the United States trade dollar. The Mint was authorized by Congress to design and create a trade dollar in the effort to improve trade with China. Prior to 1873, the Mexican peso was the predominant silver coin and the trade coin of choice.

The United States trade dollar was minted with about eight grains more silver than the domestic silver dollar. It had 420 grains of silver with a fineness of 900. In order to verify the content and fineness of the silver, the Chinese were known to place chop marks on the coins received for their goods. It was a method of protecting from counterfeit coins. These chop marks are often of particular interest to numismatics. Some consider them important while others feel the chop marks devalue the coin.

The trade dollar is very similar to its predecessor, the silver dollar. It is the same size and weight with similar portraiture as the Seated Liberty dollar. The U.S. silver dollar, however, weighed only 412.5 grains. All told, there were more than 27 million trade dollars sent overseas in trade with the Chinese.

A growing number of coin collectors are intrigued by the history and the beauty of the United States trade dollar. The points numismatics look for in a coin in pristine condition include Liberty's left knee, ear, and breast, and the head and left wing of the eagle. Depending on your collecting passion, these details may or may not be important, but they will always affect the price.