The Sheldon Coin Grading Scale is a 70 point scale used in the numismatic assessment of a coins quality. It is used by nearly all major coin grading companies, the main two being NGC and PCGS.
The grades for the scale are as follows:
AG – About Good
G – Good
VG – Very Good
F – Fine
VF – Very Fine
XF – Extra Fine
AU – About Uncirculated / Almost Unirculated
MS – Mint State
The scale was invented by William Herbert Sheldon.
William Herbert Sheldon, Jr. (November 19, 1898 – September 17, 1977) was a American psychologist and numismatist. He created the field of somatotype and constitutional psychology that tried to correlate body types with behavior, intelligence and social hierarchy through his Ivy League nude posture photos. However, his work is generally dismissed by modern researchers.