In discussing Trade Dollars on eBay, the following misconception is widely held: this Trade Dollar can't be a counterfeit from Asia because it has been in a bank vault/collection/possession of a known collector for _____  20/30/40/50 years. You may fill in the blank.  The fact is, these coins have been counterfeited almost from the time they were placed in service over 125 years ago. Toning or wear on them, therefore, may be totally original, not manufactured.  At that time, the counterfeiters were cheating unsuspecting users of the coins by adulterating the alloy, reducing or eliminating the silver content.  This gave rise to the commonly seen phenomenon of chop marks.  The chop mark indicated that the coin had been 'certified' by a bank or third party to be authentic.  Curiously, some chops would chip a small fleck of silver off the coins so that the examiner would be left with a number of ounces of silver particles for his efforts.  It is only recently that the occurence of these coins struck or cast with the correct silver content and weight has arisen due to their increases in numismatic value.  One prominent dealer in NJ suggested that this problem of counterfeiting was partially to blame for the coin's failure as a medium of exchange in China.  This may be true, but most other coins then in circulation were plagued by this type of fraud as well.  Even today, the counterfeiters produce currencies of many countries and collectible coins at a blinding pace.  See also, the previous guide under U. S. Coins, Trade Dollars, Silver Eagles, or Pandas.   Be sure and vote at the end of this guide.  It only takes about 10 seconds. Thanks. PS