The Importance of Coin Grading
If rare coin dealers only dealt with other rare coin dealers, there would be no need for coin grading. The two would simply decide on the value of the coin and conduct business accordingly. However, the coin market has expanded far beyond dealer to dealer transactions.
When the rare coin market was limited to a small number of numismatists trading with each other, three broad definitions were enough to determine grade: "Good" -- a coin with most of the detail intact; "Fine" -- a coin with clear detail and some luster on its surfaces; and "Uncirculated" -- a coin which had never been in general circulation and therefore retained its Mint State condition.
As the market grew, collectors realized that some "fine" coins were finer than others. Even some uncirculated coins rose above the rest in detail, luster, and general appearance.
Soon terms such as "very fine" and "extra fine" began to emerge, as collectors sought to further define the condition of their coins -- and increase their value. In 1948, Dr. William Sheldon, a renowned numismatist, developed the Sheldon Scale, assigning grades from "one" through "70" to coins on the theory that a "70" would be worth seventy times as much as a "one".
Although coin collectors agreed on the scale, they could not agree on the standard -- and assigning a Sheldon Scale grade to any given coin was still a matter of subjective opinion.
Historically, an adjectival system was virtually the only one used to grade coins, however, in the late 40's a numerical system was devised by an American, Dr. William Sheldon, using numbers from one to seventy. The circulated grades were assigned numbers from 1 to 59, while the numbers from 60 to 70 were used for the Mintstate grades. The basis of his number selection was the relationship of prices of early American copper coins with their grades. For example, in the late 1940’s, the price of a typical Mintstate coin (MS-60) was about five times the price of a typical Fine (F-12) example of the same date and variety. It is important to note that both the adjectival and the numerical grading systems use the same grade definitions.
Sheldon’s numerical system has been extended far beyond early American copper coins and is now the generally accepted standard for grading in most areas of North America. Not all of the numbers in the range are used, and the following are the more commonly seen numerical grades and their adjectival equivalents:

aG-3 About Good

G-4 Good

VG-8 Very Good

VG-10 Very Good Plus

F-12 Fine

F-15 Fine Plus

VF-20 Very Fine

VF-30 Very Fine Plus

EF-40 Extremely Fine

EF-45 Choice Extremely Fine

AU-50 About Uncirculated

AU-55 Choice About Uncirculated

AU-58 Very Choice About Uncirculated

MS-60 Typical Mintstate

MS-61 Typical Mintstate

MS-62 Select Mintstate

MS-63 Choice Mintstate

MS-64 Very Choice Mintstate

MS-65 Gem Mintstate

MS-66 Gem Mintstate

MS-67 Superb Mintstate

MS-68 Superb Mintstate

MS-69 Superb Mintstate

MS-70 Perfect Mintstate
Proofs, Proof-Likes and Specimens are designated with the prefixes PF, PL and SP, and further assigned a numerical grade: 60, 63, 65 and so on. Impaired pieces (those that have sustained wear through either mishandling or circulation) are assigned grades below 60, such as SP-55, and PF-50. Except in years or varieties where only Proofs or Specimens were issued, it is the exception to find a grade assigned below 50 since the surface and strike characteristics that are generally required for correct attribution are most likely gone.

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