What are grades of Morgan silver dollar?

Answer 1

All US Coins are graded on the same numerical scale numbering from 1 (lowest grade) to number 70 (highest grade). In theory a coin graded 1 would be the worst possible example of that coin and a coin graded 70 would be a perfect coin. In reality coins are graded on a scale generally as such from lowest to highest.

G-4, VG-8, F-12, VF-20, EF-40, AU-50, MS-60, MS-63, MS-65

There are many other grades between these numbers as there is no "forbidden" or "allowed" numerical grade as long as it is between 1 and 70. I suggest buying the Red Book of US Coins for a better explanation of grading.