The clarity of a diamond refers to the amount, size, type and location of internal flaws (inclusions) or surface imperfections (blemishes) visible in a diamond using your eye or a 10x magnification. All diamonds whether created or mined diamonds have imperfections in them. The less inclusions the diamond has the higher the value. Below is an illustration that shows the clarity grading scale under 10X magnification:
| GRADE |
DESCRIPTION |
| F |
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 (F 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 |
Very slightly included. The diamond contains minute inclusions such as small crystals, clouds or feathers when observed with effort under 10X magnification. |
| SI1, SI2 |
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. |
| 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. |
Both created diamonds and mined diamonds have these inclusions or blemishes that give each diamond its own unique fingerprint, making your particular diamond unique.
A diamond's ability to refract and reflect light is what makes it so brilliant and valuable and also effects the way the fancy color is displayed. The way it does this is by allowing light to enter the top of the stone, reflect off the facets that have been cut by a master diamond cutter, and reflect out the top of the stone to your eye. The fewer obstacles to this pathway there are, the greater the diamond's clarity will be, which increases the diamond's value (all other characteristics being equal).
Most diamonds, including created 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 mined 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. There is a unique inclusion that is found only in created diamonds from the "seed" that is used to grow the diamond.
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 the diamond be 'perfect'. Again, in fancy colored diamonds, the color is the most important appeal and imperfections can effect the way the color is perceived.
A diamond's clarity is measured using a jeweler's loupe (a small magnifying glass used to view gemstones) under 10-power magnification.
