Trade Dollars were an attempt at creating currency for national trade with other countries so they were called Trade Dollars and listed the metal content in grains. They were sent in numbers to China to improve trade with the United States and replace the often used silver Peso.
So Trade Dollars made their way to China mostly and made their way to some other countries like The United Kingdom. As a result some citizens of China begin making counterfeit copies of the U.S. Trade Dollar. (it was considered a form of art work in their country), and unfortunately these counterfeits made it back to the US. Some of these counterfeit Trade Dollars even fooled some experts, and many used to be sold as authentic until collectors became informed.
Many Trade Dollar collectors and novice coin buyers are still being fooled by counterfeit Trade Dollars and the authorities have made recent bust of these sells. I encourage any would be collector to check out our Trade Dollar detection guide to prevent buying fake coins. Also, don't buy these coins when you visit another country since they're more than likely countefeit and are offered at a bargain price.
A few of the tricks used by these countefeiters is to make the coin look worn and damaged so as to hide imperfections in their die making process. Also they produce Trade Dollars years and mints that the US didn't produce. If in doubt, just don't buy. Trade Dollar values are going up and it's just not worth losing your money when you can find plenty of certified examples.