What this coin looks like (obverse, reverse, mint mark location, special features, etc.): There were two major varieties of the 1880 O Morgan Silver Dollar. The first and most common is the "Normal Date" variety which features the standard 1880 date without any major errors. The other variety is the 1880/79 Morgan dollar which features an 80 over 79 overdate. This variety is fairly easy to identify because the underlying "7" is clearly visible within the top part of the "8". A small piece of the underlying "9" is also seen inside the "0" at the upper-right side. The difference between the 1880 O normal date vs 1880/79 (80 over 79) Morgan dollar varieties is depicted above in the example comparison image. Note that these are just the major varieties - there are also many VAM varieties not listed here which could fall into one of these main categories.