Your Guide to Diamond Quality: Clarity

If you’ve been following my jewelry journey these last few years, you may have heard me refer to diamonds in some very specific terms. VS-1, seventy-five pointer, F color. To me, and those who have worked in the jewelry industry for a long time, these words tell us everything we need to know about a diamond, but to those who aren’t so familiar, it can sound a bit confusing. In this series of blog posts, I am going to teach you the fast facts about diamond quality, and what makes a good diamond. You can catch up on carat weight and color in previous blog posts.  


Diamonds are graded on 4 main criteria, known as the 4Cs: Carat Weight, Clarity, Cut, and Color. This process of grading was implemented by the Gemological Institute of America (or GIA) in the med-1920s, as a way to simplify the jewelry industry and provide a universal means of grading gems. 

In our last posts, we’ve discussed carat weight and diamond color. Carat weight is a measure of the mass of the diamond, while color refers to (ironically) a diamond’s lack of color. Carat weight is measured in carats, with one carat equalling approximately 200g, and color is ranked on a scale from “D” to “Z”, with “D” being the highest color rating a diamond can receive. The most precious diamonds will have a high color rating and a large carat size, but keep in mind that, when it comes to diamonds, bigger isn’t always better. 

So, What Do You Mean By “Clarity”?

When rating a diamond’s clarity, gemologists are looking for blemishes and inclusions in the diamond. These are natural flaws that occur in the diamond-creation process; natural diamonds are formed when carbon deep in the earth is subjected to intense heat and pressure, an intense process that can lead to a variety of internal and external characteristics. External characteristics are referred to as “blemishes”, while internal flaws are known as “inclusions”. 

To evaluate clarity, gemologists determine the number, size, relief, nature, and position of these inclusions and blemishes, as well as evaluate how they affect the overall appearance of the diamond. Like color, evaluating clarity is a more subjective process than evaluating carat weight, which can be measured on a scale. While distinguishing inclusions and blemishes can be easier than determining differences in color, many of these flaws can’t be seen with the naked, untrained eye. Gemologists are trained to identify these flaws, and rank them on the scale created by the GIA. 

Like with color and carat weight, before the GIA created a standardized system for evaluating diamond quality, there was no consistent method of describing diamond clarity. Terms such as “eye clean” and “included” were vague and sometimes inaccurate. Since then, standards have been implemented when grading a diamond’s clarity. Gemologists will look at the diamond under a 10x magnification, and then plot the inclusions and blemishes they find on a diagram included in a diamond grading report. 

Based on the number and appearance of inclusions, diamond graders will then rank the diamond on the clarity scale. Diamonds can be described as:

  • Flawless (FL): No inclusions and no blemishes visible under 10x magnification
  • Internally Flawless (IF): No inclusions visible under 10x magnification
  • Very, Very Slightly Included (VVS1 and VVS2): Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
  • Very Slightly Included (VS1 and VS2): Inclusions are observed with effort under 10x magnification, but can be characterized as minor
  • Slightly Included (SI1 and SI2): Inclusions are noticeable under 10x magnification
  • Included (I1I2, and I3): Inclusions are obvious under 10x magnification which may affect transparency and brilliance

How Do I Know If My Diamond is Included?

If your diamond is natural, chances are it’s included. But this isn’t a bad thing! Inclusions are a natural part of the diamond-growing process, and indicate that your diamond is 100% authentic. Inclusions form when small crystals get trapped within the growing structure of a diamond, which can change the atomic makeup of the gemstone. The size, position, and visibility of these inclusions will have an impact on your diamond’s clarity.

Not all inclusions are created equal, either. Some inclusions will be larger, some smaller, and depending on the type of inclusion, may be more visible. The placement of inclusions within the diamond will also affect its visibility. 

Best Bang For My Buck?

Clarity is impacted not only by the inclusions within the diamond, but also by the cut and carat weight of the diamond. When diamonds increase in size, the size of their facets also increases; this makes the natural inclusions within the diamond easier to see. If you want a large diamond, choose a cut that is flattering to the inclusions within the stone, such as round or pear. The brilliant facet pattern of these shapes allow light to reflect from many different angles within the diamond, hiding inclusions to the naked eye. Emerald and Asscher-cut diamonds (also referred to as step-cut diamonds) can make inclusions more visible, as the rectangular facets are designed to emphasize transparency. You can also choose a diamond with inclusions along the sides rather than the face of the diamond, as these inclusions can be hidden by the setting of the stone. 


Want to Learn More About Diamond Clarity?

Check out these links for more!

From the GIA

From the American Gem Society

From Blue Nile

Types of Inclusions