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.
The clarity grading scale; developed by the Gemological Institute of America; has 6 categories, some of which are divided, for a total of 11 specific grades.
No inclusions and no blemishes visible in the diamond under 10 power magnification
Internally Flawless (IF)
No inclusions visible in the diamond under 10x magnification
Very, Very Slightly Included (VVS1 and VVS2)
Inclusions in the diamond so slight they are difficult for a skilled grader to see under 10x magnification
Very Slightly Included (VS1 and VS2)
Inclusions in the diamond are observed with effort under 10x magnification, but can be characterized as minor
Slightly Included (SI1 and SI2)
Inclusions in the diamond are noticeable under 10x magnification
Included (I1, I2, and I3)
Inclusions in the diamond are obvious under 10x magnification which may affect transparency and brilliance
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 diamond clarity is extremely important.
How did the GIA Clarity Scale come to be?
Like the color scale, GIA's clarity grading system developed because jewelers were using terms that could be misinterpreted, "loupe clean" or "piqué™. Today, even if you buy a diamond somewhere else in the world, the jeweler will most likely use terms like VVS1 or SI2, even if his or her language is French or Japanese instead of English.
What causes diamond inclusions?
Small crystals can become trapped in a diamond when it's forming. Sometimes as a crystal grows it can develop irregularities in its atomic structure.
In closing, knowing all the 4Cs of diamonds inside and out makes you a much more educated and empowered diamond consumer. Wouldn’t you all agree?