PCGS (Professional Coin Grading Service) is a prominent third-party service that authenticates, grades, and encapsulates coins using the 70-point Sheldon grading scale. A coin's grade is based on its overall condition, including factors like strike, luster, surface quality, and eye appeal. 

The PCGS grading scale

Mint State (MS) 60–70: Uncirculated coins
These are coins that have never been used in circulation. The grade is determined by the severity and number of post-minting marks, with 70 being the highest possible score. 

• MS-70: A perfect coin with no visible flaws, even under 5x magnification. It has an exceptional strike and full original luster.
• MS-69: A coin with a near-perfect strike and full luster, but with one or two very small, non-detracting contact marks.
• MS-60: An unattractive coin with numerous large marks, hairlines, or scuff marks, but with no evidence of circulation wear. 

About Uncirculated (AU) 50–58
These coins have only the slightest traces of wear on the highest points of the design. 

• AU-58: A coin with the faintest sign of wear on only one or two high points, and with nearly full original luster.
• AU-50: A coin with traces of wear on nearly all of the highest points and at least half of the original mint luster. 

Extremely Fine (EF/XF) 40–45
These coins have light, overall wear on the highest points, but all major design details remain sharp. 

• EF-45: A coin with light overall wear, and mint luster may still be present in protected areas.
• EF-40: This grade has slightly more extensive wear than EF-45 but retains excellent sharpness. 

Very Fine (VF) 20–35
The coin shows moderate wear on the surface, but all lettering and major features are still sharp. 

Fine (F) 12–15
The coin shows moderate to considerable, even wear, but the entire design remains bold. 

Very Good (VG) 8–10
A well-worn coin with major designs visible, but faint in some areas. The head of Liberty or other features are visible in outline form without central detail. 

Good (G) 4–6
A heavily worn coin where the major designs are visible, but large areas are flat and without details. 

About Good (AG) 3
The coin is very heavily worn, with portions of the lettering and date being worn smooth. 

Fair (FR) 2 and Poor (P) 1
These are the lowest grades, designating coins that are extremely worn to the point of being barely recognizable. 

Problem coins (Details Grade)

Coins that cannot be assigned a straight numerical grade are encapsulated in a "Genuine" holder and given a "Details" grade. This happens for problems such as: 

• Cleaning: A coin that has been abrasively cleaned to the point that it leaves hairlines or surface damage.
• Damage: Significant scratches, nicks, or rim damage.
• Environmental damage: Corrosion or other issues caused by the coin's surroundings.
• Counterfeits: Inauthentic coins are not graded and are marked as counterfeit. 

Important PCGS designations

In addition to the numerical grade, PCGS may add specific designations to a coin's label: 

• Plus Grades (+): For coins with exceptional eye appeal for their assigned grade.
• Color (Red, Red-Brown, Brown): Used for copper coins to indicate the amount of original red color remaining.
• Prooflike (PL): Used for Mint State coins that show a mirror-like finish.
• Deep Mirror Prooflike (DMPL): Indicates an even more reflective finish on a coin.
• First Strike: Given to coins that were issued within the first 30 days of a mint's release. 

*All info is from their website this is for quick reference