Almost all diamonds contain very tiny natural birthmarks know as inclusions. To determine a diamond’s clarity an expert views it under powerful magnification. The fewer the inclusions, the rarer and more valuable the diamond. Each of these natural characteristics are documented in the diamond’s laboratory certificate which creates an easily identifiable record of that specific stone.
Most inclusions are not discernable to the naked eye and require magnification to become apparent. A laboratory-certified-clarity rating of SI2 represents the point at which inclusions are technically not visible to the naked eye. Clarity is graded, using a very precise and complex method of evaluating the size, location and visibility of inclusions. The chart above will give you an example of the type of inclusions that may fit in each category. Clarity is graded using the following terms:
Flawless (FL) - No inclusions or blemishes are visible to a skilled grader using 10× magnification.Internally Flawless (IF) - No inclusions and only blemishes are visible to a skilled grader using 10× magnification.Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification.Very Slightly Included (VS1 and VS2) - Inclusions are clearly visible under 10× magnification but can be characterized as minor.Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader using 10× magnification.Included (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance. This category is also commonly referred to as Imperfect.
Grading scale courtesy of the GIA.
The 4 C's of Diamond Value
Watch the Video (3min)Gemological Institute of America