Diamond clarity refers to the absence of inclusions and blemishes.
Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. The process can result in a number of natural particles, called 'inclusions' or external characteristics, called 'blemishes'.
When evaluating clarity, the grader uses magnification and specific lighting and considers the effect these characteristics have on the diamonds appearance and durability.
Two common inclusions are crystals and feathers. Crystals are merely minerals trapped inside the diamond; feathers are breaks in the diamond. Blemishes are usually very small and are only found on the surface of diamonds.
The American Gem Society grades clarity on the scale of 0(zero) to 10, zero being the best clarity.
The Gemological Institute of America grades clarity ranges from FL to I3, FL being flawless.
The higher clarity grades are more valuable, however, many people consider that inclusions add 'character' to the diamond.