The Guide to Diamond Clarity

The internationally recognized diamond grading scale was established in 1953 to develop terms that can’t be misinterpreted. It has 6 categories and some of these categories are divided into two levels, creating a total of 11 possible diamond clarity grades. The scale breaks down as follows:

Flawless (FL)

For a diamond graded as FL, it means there are no inclusions or blemishes visible under 10x magnification. This is a diamond that is “flawless” inside and out. While they likely have some inclusions, they are too small to see with a microscope under this level of magnification, so they have no effect on the clarity grade. FL and IF diamonds account for about 2% of the diamond market, making them incredibly rare and very expensive.

Internally Flawless (IF)

A diamond graded as IF means there are no inclusions visible under 10x magnification. This is a diamond with blemishes but no inclusions. Blemishes exist externally on the diamond’s surface, so they can often be polished away, and when they’re minor, they won’t affect the clarity grade too much. Inclusions that exist inside the stone carry the most impact. This is why clarity grading focuses mainly on assessing inclusions.

Very, Very Slightly Included (VVS1 and VVS2)

Diamonds graded as either VVS1 or VVS2 show inclusions that are so slight, they are difficult for a skilled grader to see under 10x magnification. These inclusions are barely noticeable under magnification, and most consumers cannot tell the difference between FL, IF, and VVS diamonds. Diamond stones in the VVS range have extremely high clarity and will still command high prices.

Very Slightly Included (VS1 and VS2)

Diamonds with a grading of either VS1 or VS2 means that inclusions are observed with effort under 10x magnification, but can be characterized as minor. This upper-middle range of diamond clarity grades indicate minor inclusions that don’t really interfere with clarity even though they’re larger and more numerous than those in VVS diamonds.

Slightly Included (SI1 and SI2)

With a grading of either SI1 or SI2, it means that diamonds will have inclusions that are noticeable under 10x magnification. Approximately ⅓ to ½ of diamonds graded SI1 will not have inclusions that are visible to the naked eye, therefore this is the cut-off grade for us and every stone with this clarity grade should be examined carefully for eye visible inclusions. Most SI2 clarity graded diamonds will have visible inclusions, and some may even appear cloudier or less brilliant because the inclusions are more likely to interfere with light reflection.

Included (I1, I2, and I3)

The lowest grading for a diamond’s clarity, a rating of I1, I2, or I3 means that inclusions are obvious under 10x magnification, which may affect transparency and brilliance. Diamonds in the I range have inclusions obvious to the naked eye. These inclusions may also be so significant that they can affect the diamond’s durability and integrity.

Diamond grades are assigned to diamonds by professional and skilled graders after looking at stones face up under 10x magnification with a microscope. In their assessment, they’re considering five diamond clarity factors:

Size

Size is the most important factor when assessing an inclusion. A large inclusion will have a much more significant impact on a diamond’s visual appeal than a small inclusion.

Number

The quantity of inclusions will matter more significantly based on the size and location. However, even tiny inclusions can make a diamond less attractive if too numerous.

Location

The location of inclusions will affect its visibility. The worst location is the table facet since the table serves as a window into the stone. Inclusions around the girdle can often be hidden by certain settings. And inclusions directly above the culet can sometimes be reflected within the diamond making it appear to multiply.

Relief

This refers to the color or contrast of the inclusion. Clear or white inclusions will have less of an impact than darker inclusions, like graphite crystals. When an inclusion is closer to the gemstone’s color and refractive index, the lower its relief and therefore, is less obstructive to the visual appeal.

Nature

Different types of inclusions will impact diamond clarity to varying degrees. For example, pinpoints – tiny crystals barely visible under 10x magnification – will have little effect on diamond clarity. Twinning wisps – white lines that form when the diamond crystal changes direction while growing – can make the diamond appear cloudy sometimes, while appearing barely noticeable in other instances.

When considering a diamond purchase and the clarity grading you want to pursue, some of the best advice we have is to focus on choosing an eye clean diamond. Diamonds with clarity grades of VVS, VS, and SI can all appear as eye clean with no visible imperfections to the naked eye. With eye clean clarity, the inclusions are not disturbing light reflection to the degree that they’re dulling the brilliance, sparkle, and overall beauty of the diamond.

For example, take a look at these two oval diamonds side by side. They are extremely similar in cut, color, and carat weight, but one is graded VS1 and the other SI1 for their clarity. That’s a significant difference on the grading scale, yet each is a beautiful, eye clean diamond. And, the difference in clarity leads to over a $4,000 difference in price. You’ll find substantial price differences when moving up or down the clarity grading scale. As clarity grades go up, the price differences increase exponentially, and vice versa when going down in grades.

Diamond shape and size can also greatly affect clarity, in some instances. The larger the carat and size of the diamond, the more surface area will be visible. The more surface area means that inclusions and blemishes will be more obvious. For this reason, diamonds larger than one carat are best suited for a clarity grading of VS2 or higher.

When considering a diamond’s shape affecting clarity, step cut diamonds like emerald and Asscher cuts require a higher clarity grade due to the rectangular facets emphasizing transparency and a deep view into the diamond. For these step-cut shaped diamonds, you will need a clarity grade of at least VS1, and most likely VVS2 or better to achieve eye-perfectness.

And finally, don’t make too much of the plot diagram that appears on the diamond’s certification. These plot diagrams help to identify the diamond and chart the five clarity factors. It’s a nice visual representation of these characteristics. While you may want to ask questions about the severity of the inclusions or blemishes, the fact that you see inclusions on the diagram doesn’t mean they’ll be noticeable when looking at the diamond.

Diamond clarity is a fundamental piece of the picture when considering any diamond. Knowing these details will help you make the best, informed choice for your diamond, but always remember to view a diamond in its entirety to see for yourself how a diamond’s clarity impacts its beauty and sparkle.