No diamonds are entirely without inclusions or blemishes, and these characteristics help gemologists accurately determine natural diamond clarity.
Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’
Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.
Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader. To the naked eye, a VS1 and an SI2 diamond may look exactly the same, but these diamonds are quite different in terms of overall quality. This is why expert and accurate assessment of clarity is extremely important.
You can also take a closer look at the Diamond Grading Scales.
Clarity diagrams are for reference only and do not reflect true diamond clarity quality grades. Images are not for clarity diamond grading.
Updated: GIA report scales have been updated with the newest scales as of May 2014