What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
One major variety is the 1880/79 S Morgan Silver Dollar with an 80/79 overdate from the San Francisco Mint (sometimes known as VAM-8 or VAM-9). This coin features an 1880 date struck over the previous year of 1879 date - which resulted in an 80 over 79 date. This variety is fairly easy to identify because the underlying "7" is clearly visible within the top part of the "8" as a small rough patch. A small piece of the underlying "9" is also seen inside the "0" at the upper-right and even small piece at the bottom-left side. The difference between the 1880 S normal date vs 1880/79 vs 1880/9 Morgan dollar varieties is depicted below in the example comparison image:
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD