The natural formation process of a diamond over millions of years results in unique internal and surface characteristics, known as inclusions and blemishes, which determine its clarity.
The grading system for clarity ranges from Flawless to I3 and plays a crucial role in determining the value of a diamond as flawless stones, showing no imperfections under 10x magnification, are exceedingly rare. The relationship between clarity, rarity, and value highlights the importance of this characteristic in assessing a diamond's quality and price.