Coins are rarely exactly one grade or another. The following grading scale is a guide only as grading is based more on ones opinion and can vary from person to person.

GEM - Uncirculated 

The highest grade a coin can reasonably be expected to occur in, the strike of the coin will be strong, detracting marks will be very minimal , the coin will have virtually full lustre and a patina or toning may be present, the coin will have strong eye appeal.

CHOICE - Uncirculated 

The coin should be fairly well struck although some weakness due to the type of coin or wear of the die is still acceptable. The coin will have a minimum of detracting marks and should still show a large percentage of mint lustre, this coin should also have nice eye appeal.

UNC - Uncirculated

A coin that has not been circulated, shows no wear and mint lustre will be evident however, the coin can have been struck from worn dies, (coins struck from worn dies will be indicated as a weak strike in the description, whereas a coin struck from a near new die will often be described as well struck!)  Some detracting marks may be evident due to modern minting methods coins striking against each other, this is often referred to as bag marks!, this also occurs during initial shipping from the issuing mint to the banking authorities.

aUNC - Almost uncirculated

Similar to Uncirculated but will show some minor traces of wear on the high points, the coin still shows a good % of mint lustre.  This grade of coin will exhibit a very small amount of wear due to minimal circulation.

EF - Extremely fine

A coin that has had a short period of circulation and will show very slight wear on the high points that is barely noticeable to the naked eye.  However, consideration should be given to the original striking of the coin and the condition of the dies, a worn die may result in a softly struck coin which is in fact uncirculated, some mint lustre may be apparent..

VF - Very fine

A coin that shows obvious signs of circulation, the high points and more intricate parts of the design will be completely worn away, some minor edge knocks and rim damage may be present. The coin should still be collectable with all the main features and details clear.

F - Fine

Shows extensive signs of circulation, most of the details are worn away although the general design will still be evident.

VG - Very good

The lowest collectable grade a coin can be given, will show extreme wear but the basic design and date will still be readable.