To evaluate diamond clarity, professional graders use 10x magnification to determine the number, size, relief, nature, and position of imperfections and how they impact the overall appearance of the stone. Once each inclusion or blemish is assessed, the diamond is assigned one of the 11 specific clarity grades. Then, each imperfection is plotted on a visual diagram that helps identify the diamond's one-of-a-kind markings.
Size
Generally, the larger the inclusion is, the more impact it'll make on the clarity grade (though the size of the inclusion is always relative to the size of the stone). Extra-large, close to the surface, or surface-reaching inclusions can also impact a stone's durability.
Number
Inclusions are judged on how visible they are vs. how many there are. However, generally, the more significant the number of clarity characteristics there are, the lower the clarity grade will be.
Position
Position references the location of the inclusion or blemish in the diamond. Imperfections can occur anywhere within or on a diamond, though inclusions nearest to the table tend to have the most significant impact on clarity.
Nature
The nature of an imperfection refers to the kind of inclusion that it is and the depth at which it occurs within the diamond. Internal characteristics are called inclusions, while external characteristics are called blemishes.
Relief
Relief references the distinctness of the inclusion or blemish in contrast with the diamond. A transparent or white inclusion is considered low relief, while a dark inclusion is considered high relief. The greater the relief is, the more of an impact it'll make on the overall clarity.
