Let’s dive deep into the factors affecting diamond clarity

Few things in nature are absolutely perfect. This is as true of diamonds as anything else. Diamonds have internal features, called inclusions, and surface irregularities, called blemishes. Together, they’re called clarity characteristics. Clarity is the relative absence of inclusions and blemishes.

Among other things, blemishes include scratches and nicks on a diamond’s surface. Inclusions are generally on the inside, and some might break the surface of the stone. Sometimes, tiny diamond or other mineral crystals are trapped inside a diamond when it forms. Depending on where they’re located, they might remain after the stone has been cut and polished, and they can affect a diamond’s appearance.

Clarity characteristics might have a negative influence on a diamond’s value, but they can have positive effects as well. For one thing, they help gemologists separate diamond from imitations. (This is easier with included diamonds than with flawless ones.) And because no two diamonds have exactly the same inclusions, they can help identify individual stones. They can also provide scientists with valuable information about how diamonds form.

clarity closeup

No two diamonds have exactly the same clarity characteristics in exactly the same locations. This fact helps gemologists identify individual diamonds.

Like the rest of the Four Cs, clarity’s influence on value is directly related to the concept of rarity. Flawless is the top grade in the GIA Clarity Grading System. Diamonds graded Flawless don’t have visible inclusions or blemishes when examined under 10-power (10X) magnification by a skilled and experienced grader.

DE 2 CLARITY 2004 copy.QXD

As clarity increases, and if all other value factors are equal, diamond price per carat also increases.

Flawless diamonds are very rare—so rare, in fact, that it’s possible to spend a lifetime in the jewelry industry without ever seeing one, and they command top prices.

At the other end of the scale are diamonds with inclusions that can be easily seen by the unaided eye. Between the two extremes are diamonds with inclusions visible only under 10X magnification. Stones in the middle range make up the bulk of the retail market.

There are 11 clarity grades in the GIA clarity grading system. They are Flawless, Internally Flawless, two categories of Very, Very Slightly Included, two categories of Slightly Included, and three categories of Included.

The effect of a clarity characteristic on the clarity grade is based on its size, number, position, nature, and color or relief.


The GIA clarity scale includes eleven diamond clarity grades. The scale narrows at the top because there are very few diamonds in the higher clarity grades.

Sometimes, one factor makes more difference to the clarity grade than the others. But it’s not always the same one. The relative importance of each factor varies from diamond to diamond. For example, an inclusion off to the side of a stone would have less impact on clarity than the same size inclusion located directly under the table. In this case, the position is probably the determining factor.

clarity closeup inclusions

A clarity characteristic’s effect on a diamond’s clarity grade is determined by five factors: size, number, position, nature, and color or relief. – Gary Roskin GG, FGA

Occasionally, if an inclusion has the potential to cause damage to a stone, it can affect the grade. But this is rare, and usually applies only to Included (“I”) diamonds.

Diamond professionals use a set of terms that originally included very very slightly imperfect, very slightly imperfect, slightly imperfect, and imperfect. In recent years, the term imperfect has been replaced with included. (GIA uses included in its clarity grading system.)

These terms were shortened to the initials VVS, VS, SI, and I. The abbreviations eventually gained acceptance throughout the international diamond community. Their use is now widespread regardless of how the words they stand for translate into various languages. Very may translate to tres in French, for instance, but in France a very slightly included diamond is still a VS. Even a country like Russia, with a completely different alphabet, uses the same abbreviations.

Content and imagery courtesy GIA