What This Coin Looks Like (Obverse, Reverse, Mint Mark Location, Special Features, etc.): One major variety is the 1887/6 O Morgan Silver Dollar featuring a 7 over 6 overdate. An 1887 date was struck over an 1886 date on the die which resulted in parts of the underlying "6" appearing near the bottom half of the "7" in the date. A large curve from the underlying "6" is seen on the bottom-right side of the "7" as depicted by the arrows in the example closeup image below:
Coin Value Chart: Typical Coin Prices, Values and Worth in USD based on Grade/Condition