My Profile  |  Contact Us  |  Member Portal

American Gem Society Logo

Understanding Diamond Clarity: The 4 Cs of Diamonds

What is Diamond Clarity?

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.

Diamond Grading

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. Learn more about how to interpret a plot on the report.

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

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.

AGS Diamond Clarity Scale

Clarity is considered important in the value of a diamond because of the notion that diamonds with a higher clarity are rarer in nature. 

The Bottom Line

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.