Understanding Diamond Clarity: the 4 Cs of Diamonds
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Clarity is the state of being clear or transparent. Diamond clarity is the presence or absence of characteristics called inclusions in the diamond.

When grading the clarity of a diamond, the lab determines the relative visibility of the inclusions in a diamond and their impact on the overall visual appearance.

So, what are these inclusions that affect clarity? In short, inclusions are the internal or external flaws of the diamond. The size and severity of these flaws determines the grade.

If you want to know more about inclusions, we go a bit further into detail in our Diamond Inclusions section.


Since many inclusions and blemishes are very small, and can be difficult to see with the naked eye, they are graded at 10x magnification. Grading at 10x is an industry standard to determine the final clarity grade of the diamond.

Diamond graders plot the inclusions they see in the diamond on a diagram which is included on diamond grading reports. See how AGS Lab diamond graders plot diamonds.

Clarity grade is determined on a scale of decreasing clarity from the highest clarity (Flawless or FL) to the lowest clarity (Included 3, or I3).


The clarity scale originated because jewelers were using terms that were unstandardized and could be easily misinterpreted. Descriptive terms such as “eye clean,” or “included” were vague and didn’t communicate the clarity of the diamond effectively.

The modern clarity scale was invented in the 1950s, by a former president of GIA, Richard T. Liddicoat, Jr. With minor modifications, it has been the universal standard ever since, using verbal descriptors most are now familiar with: Flawless, Internally Flawless, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, and I3.

Learn more about the Clarity Scale and what it means.

AGS Rock Stars note:  Diamond size and cut can have an effect on clarity.  It’s easier to see an inclusion in a larger diamond than a small one. It’s also easier to see inclusions in diamonds with fewer facets, such as an emerald cut.

Clarity is considered important in the value of a diamond because of the notion that diamonds with a higher clarity are rarer in nature. Check out some examples of diamond clarity and learn why it is so important.


It’s important to have your diamonds graded by a credentialed expert or a reputable diamond grading laboratory. Look for AGS jewelers to find reputable AGS member stores.


Mission Statement

The American Gem Society (AGS) is a nonprofit trade association of fine jewelry professionals dedicated to setting, maintaining and promoting the highest standards of ethical conduct and professional behavior through education, accreditation, recertification of its membership, gemological standards, and gemological research.

The Society is committed to providing educational products to inform and protect the consumer and to contributing to the betterment of the trade by creating industry standards to protect the jewelry-buying public and the fine jewelry industry as a whole.

AGS Laboratories, founded to support the AGS mission, is a nonprofit diamond grading laboratory with a mission of consumer protection. Adhering to the AGS Diamond Grading Standards, AGS Laboratories is dedicated to offering diamond grading reports that provide consistency and accuracy based on science.

American Gem Society