Very tiny inclusions are called pin points. A cluster of many pinpoint inclusions is called a cloud. Bearding refers to tiny cleavages that occur around the girdle of a diamond. Bearding may form during cutting or it may sometimes occur when the stone is worn. Exterior problems are called blemishes. They include chips, scratches, cavities, extra facets, and naturals, which are places where the diamond has not been polished and the original surface of the crystal remains.
 

The type, size, number, and placement of flaws are important factors in determining a diamond's clarity grade. If an inclusion is visible through the table it is considered more detrimental to the clarity grade than the same inclusion would be if it were closer to the girdle. Also, if the flaw is detrimental to the durability of the diamond, such as a large cleavage could be, it would have a more drastic effect on the clarity grade than if it were an included crystal. The size of flaws is very important: only the most minute flaws are found in the higher diamond clarity grades. The larger the flaw, the lower the grade. The number of inclusions also affects the clarity grade. Even when a diamond has very small flaws, if there are enough of them, the diamond could be penalized with a lower grade.

The Gemological Institute of America also devised the accepted clarity grading system. Diamonds are graded for clarity under ten power (l0X) magnification. The GIA clarity grading system includes ten clarity grades:

FLAWLESS - no visible inclusions under l0X magnification when the diamond is graded by a diamond expert; there are no detrimental surface blemishes on a flawless diamond.

VVS-1, VVS-2 - (very, very slight imperfections) The inclusions in this grade are extremely small and few in number; the inclusions would be very, very difficult to find by a diamond expert under l0X magnification.

VS-1, VS-2 - (very slight imperfection) In this grade there a few inclusions but they are relatively hard to find by a diamond expert when examined under 10X magnification.

SI-1, SI-2 - (slight imperfections) In this grade there are inclusions that are fairly easy to find under l0X magnification by an expert, but they are not eye visible without magnification. In an SI grade stone the inclusions do not obstruct the brilliance nor are they a great detriment to the durability.

I-1, I-2, I-3- (imperfect) These grades encompass a broad range of inclusions. A better I-1 diamond may have many small flaws that do not interfere with brilliance or durability. An I-1 may have not eye visible flaws, but a lower I-1 grade can have minor problems with durability and/or have minor eye visible flaws. An I-2 grade definitely has something that is eye visible and it may have cleavages that could affect durability. Brilliance in an I-2 is definitely impaired. An I-3 grade is the lowest possibility: it will have major problems of durability and large eye visible inclusions. Brilliance is cut down considerably.

In the subgrades,"1" is better than "2". In the VVS grade the difference between a VVS-1 and VVS-2 is extremely minor, but as the clarity grades get lower, the differences between a "1" and "2" becomes greater. There is a vast difference in the range between I-1 and I-2.

Clarity grading of a diamond is an informed opinion. It is very difficult to define in exact terms. Each diamond is individual and most will fall easily into one of the ten clarity grades but a few are debatable and fall on the border lines. Two diamond experts could disagree on the clarity grades of some stones.

When you are buying a diamond ask the seller to diagram the inclusions and point them out to you under magnification. Keep in mind you may not be able to see the smallest flaws.
                                                    
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