Another vital diamond grading characteristic is their clarity. This refers to the number, position and size of the inclusions that occur naturally inside diamonds. The fewer and less obvious the inclusions, the more valuable the diamond. Here is an illustration that shows the clarity grading scale that has been established by the world's foremost authorities on diamonds:
| Grade |
Description |
| FL |
Flawless. The diamond shows no inclusions or blemishes of any sort under 10X magnification when observed by an experienced grader. Note: Truly flawless or internally flawless (FL or IF on the GIA's grading scale) diamonds are extremely rare |
| IF |
Internally Flawless. The diamond has no inclusions when examined by an experienced grader using 10X magnification, but will have some minor blemishes. |
| VVS1,VVS2 |
Very, Very slightly included. The diamond contains minute inclusions that are difficult even for experienced graders to see under 10X magnification. |
| VS1,VS2 |
Slightly included. Inclusions are obvious under 10x magnification and may or may not be visible to the naked eye. However, when set in jewelry, the inclusions may become less visible. |
| SI1,SI2,SI3 |
Very slightly included. The diamond contains minute inclusions such as small crystals, clouds or feathers when observed with effort under 10X magnification. |
| I1,I2,I3 |
Included. Inclusions are obvious under 10x magnification and are usually visible to the naked eye. This quality allows for a larger diamond to be purchased at a lower price. |
It is these inclusions or blemishes that give each diamond its own unique fingerprint, making your particular diamond truly yours. In fact, the independent grading report that comes with every diamond we sell will show a diagram indicting any characteristic your diamond, indicating any blemishes your diamond may have, as well as their location. The most important thing to remember when it comes to clarity is that a diamond's inclusions should not be noticeable to the naked eye, nor should they be so excessive that they affect the diamond's durability.
A diamond's ability to refract and reflect light is what makes it so brilliant and so valuable. The way it does this is by allowing light to enter the top of the stone, reflect pathway there are, the greater the diamond's clarity will be, which increases the diamond's value (all other characteristics being equal).
Most diamonds contain some blemishes (crystals, clouds, or feathers), which can be found inside the stone (called inclusions). Surface blemishes are not considered a major concern, since they can often be polished away. Crystals are mineral deposits trapped inside the diamond; clouds are small specks or hazy areas that give a milky appearance; and feathers are small cracks that are shaped like a bird's feather.
Naturally, inclusions that don't impede the light's passage through the diamond or visibly decrease its beauty will not have a substantial effect on its value. It is more important that any blemishes do not affect the stone's attractiveness or durability, than that the diamond be 'perfect'. A diamond's clarity is measured using a jeweller's loupe (a small magnifying glass used to view gemstones) under 10-power magnification. The FTC requires all diamond grading be done under 10-power magnification; any inclusions not detected under this magnification are considered to be non-existent.