The way we think of clarity, is like birth marks; diamond clarity is the birthmarks that diamonds have on the inside of the stone. The more pure the clarity, the more brilliant the diamond. Diamonds are graded according to their combinations of Monte mineral traces and crustal dislocations called inclusions. Flawless diamonds are extremely rare and valuable because the fewer the inclusions, the less interference with the passage of light, and hence its greater sparkle.
Inclusions vary from flawless (FL) to imperfect (I3) with a number of grades in between the two extremes. Flawless diamonds are exceedingly rare and are best suited to diamonds that have a colourless grade (typically D-F range). A clarity grade of I3 which means that the diamond has inclusions which may be visible to the naked eye are best suited to lower colour grades as the inclusions won’t be as evident.