In this article, we will look at a few examples of added mint marks. Added mint marks are commonplace with several series of U.S. coins. The easiest way to distinguish between genuine and added mint marks is to know the subtle nuances of an original coin. For instance, on Morgan dollars, there is a significant difference in luster between dollars produced in San Francisco and those minted in Philadelphia, as well as the strike of the coin. An "S" mint mark adhered to a Philadelphia dollar is the most commonly encountered Morgan counterfeit.
Most of the added mint marks occur on Mint State coins, excluding the 1893-S dollar that is almost always encountered in circulated condition. On most genuine "S" mint dollars, the luster is very vibrant and usually slightly PL, with an above-average strike. That is different from the usual "P" mint dollar that has a much more subdued, satiny look with an average strike at best. Because mint marks were individually hand punched and most dates have too many dies, you cannot rely on using the placement of the mint mark to guarantee the authenticity.
There are two different ways in which these coins are counterfeited. The most difficult method, yet the hardest to detect, is achieved when the counterfeiter shaves an "S" off a common-date genuine Morgan dollar. Occasionally the counterfeiter will shave off a mint mark that is not appropriate in size for the year that he is trying to copy. For instance, a large "S" shaved off an 1880-S Morgan would not be appropriate for adding to an 1884-S Morgan that should have a smaller "S" mint mark. This goes right back to my original point of how important it is to learn the characteristics of genuine coins within the set you are collecting.
The second way to make these counterfeit mint marks is to make the "S" from scratch. This is usually achieved by added silver solder directly to the coin and then shaping an "S" in attempting to duplicate a genuine mint mark. This method is definitely more crude as it is very hard to square off the serifs properly and get them perfectly perpendicular to one another. I have seen "Ss" added to almost every scarce and rare-date Morgan, so don't let your guard down!