What this coin looks like (obverse, reverse, mint mark location, special features, etc.): One major variety is the 1880 CC 8/7 Morgan Silver Dollar featuring the reverse of 1879 and also an 8 over High 7 overdate from the Carson City Mint (sometimes known as VAM-5).
Carson City Morgan dollar varieties either have the earlier Reverse of 1878 or Reverse of 1879 from the previous year. The reverse of 1878 is actually the earlier design which can be identified by noticing how the eagle had an unnaturally flat or concave breast. The easiest way to identify this variety is to look at the arrow feathers on the arrows that the eagle is holding in it's claw. The top feather is straight and parallel along with the rest of the arrows.
The later reverse of 1879 variety was changed to give the eagle a rounder and more convex breast appearance that looked more natural. Again the easiest way to identify the reverse of 1879 is to also look at the arrow feathers. Unlike the reverse of 1878 - the reverse of 1879 features a prominently slanted top feather on the arrow. The difference between the Reverse of 1878 vs Reverse of 1879 Morgan Silver Dollar is depicted below in the example comparison image with the features depicted by the arrows:
This variety also has an 1880 date struck over an 1879 date which resulted in parts of the underlying "7" being clearly visible within both the top and bottom portions of the "8". The bottom of the "7" is also seen as a bar or dash below the number "8" - although it is positioned higher and closer to the "8" than the "8 Over Low 7" variety as depicted by the arrows in the example image below. The difference between the 1880 CC 8 Over 7 varieties (normal date vs low7 vs high 7) CC Morgan Silver Dollar varieties (all featuring reverse of 1879) is depicted below in the example closeup comparison image:
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD