Unlike the other value factors, clarity is the most talked and heard about. Grading clarity simply means looking for the clarity characteristics, which are classified as Inclusions (Internal) and Blemishes (External). Judging the impact of these characteristics would decide a stone's relative position on a Flawless-To-Imperfect scale; where Flawless meaning the absence of any internal & external characteristics and Imperfect diamonds being those which contain inclusions & blemishes which are obvious to the unaided eye.
To judge this impact five factors are taken into consideration - The size, nature, position,relief or colour, and number of the clarity characteristics. E.G.L., uses the gemological microscope to locate inclusions & blemishes. However, the clarity grade is called on the basis of the impact of the impurities under a 10X loupe, since the diamond industry goes by the 10x loupe for clarity grade.