Diamond Clarity: 5 Things You Must Know

The level of clarity is a measure of the number and quality of diamond inclusions. 

The number of inclusions and blemishes in diamonds is a good indicator of clarity. Diamonds are formed underground under extreme heat and pressure. Most diamonds have impurities or other inclusions.

The surface of diamonds can also contain unique features like flaws. .. Nature has very few flawless diamonds.

How clarity is evaluated:

Diamonds are observed by a trained gemologist under 10x magnification. Then, an evaluation is given from ‘flawless’ to ‘included’. 

It is easier to locate the clarity feature the larger the diamond.


A feature is fully enclosed within the diamond and another is visible from the surface.

It is a term that refers to foreign substances, such as mineral crystals other than diamond formed in the ground. Also, it can be used to describe traces of distortion of crystal structure like cracks and crevices.

Blemish (scratch)

This characteristic is limited to the surface and can show scratches and chips.

How diamond clarity is measured:

The 4C diamond clarity scale, which determines the clarity grade, is divided into 6 major categories and subdivided child categories based on strict criteria, and is evaluated on a total of 11 levels.

Why diamonds with fewer inclusions are more valuable

Many rough diamonds have defects in appearance such as inclusions and flaws, so polish them while avoiding these defects. 

As a result, yield (weight) is often sacrificed, and flawless diamonds are so rare that they are extremely valuable in intact areas such as Flawless and IF. 

This “rareness” and the “beauty” created by the high transparency are the reasons why diamonds without defects are more valuable.

However, on the other hand, since no two diamonds have exactly the same inclusions in the exact same place, the presence of inclusions is a testament to the nature of the diamond and the originality of the diamond.

As a result, high-value, intact diamonds are more difficult to distinguish than diamonds with inclusions.

Clarity grades

FL: Flawless

It is the highest rated clarity grade that even if a skilled grader inspects it 10 times larger, it can not confirm any inclusions, flaws, etc., both inside and outside. It is said that many people in the jewelry industry have never seen it, and it is an extremely rare grade that is rarely distributed in the general market.

FL diamond 02

For round brilliant diamonds, “Flawless Clarity, D Color, VVS1 Clarity” is the perfect combination, and for large diamonds, it is recognized as a special grade with asset value. Both loupe and microscope inspections are required for grade evaluation.

Since flawless has extremely few defects, it is difficult to identify individuals due to flaws. Therefore, the most reliable way to confirm the identity of a diamond and a certificate is to confirm the girdle stamp number with a laser beam.

  • Natural limited to girdle width (small edges of rough diamonds left on the surface of polished diamonds)
    are almost invisible to the naked eye. However, if Natural flattens or dents the girdle contours, it will affect the grade.
  • Extra facets on the pavilion that are not visible face-up (extra cut faces not required for cut style)
  • Laser engraving that can be judged not to have entered the inside when observing face-up at 10x magnification
  • Internal graining (growth line *) that is not reflective, does not take on white or other colors, and does not impede transparency.

 IF (Internally Flawless)

It is a quality that can confirm no defects inside and very fine scratches on the outside. It is the highest quality clarity grade on the market as well as Flawless. Even if a skilled grader is magnified 10 times, no defects such as inclusions can be found inside. Checking IF level surface defects is very difficult even with a skilled grader.

IF diamond 02

The difference from flawless can is at the microscope level, and the only grades that cannot be confirmed with inclusion inclusions at 10x are flawless and IF.

Due to the quality with extremely few defects, the identity is confirmed by the girdle confirmation number etc. like Flawless.

Since the scratches on the surface of the IF are very slight and can only be confirmed with a microscope, there is no description as an individual clarity feature in the certificate. Instead, the Crarity Characteristics section of the IF’s certificate will always include the comment “Minor Details of Polish”, “No blemishes are shown”.

VVS1: Very Very Slightly Included 1

It refers to the state with very few inclusions.

Even if a skilled grader is magnified 10 times, it is extremely difficult to distinguish inclusions by face-up observation, and it can only be found by face-down.

VVS1 diamond 02

VVS-class diamonds have few shortcomings, as it is difficult for even a seasoned grader to determine the exact criteria under normal circumstances. It is the highest class clarity grade with excellent quality in general distribution.

VVS2: Very Very Slightly Included 2

It is the second highest rating after VVS1 even in the evaluation that it contains only a very small amount of inclusions.

VVS2 diamond 02

Even if a skilled grader is magnified 10 times, it is very difficult to recognize inclusions, etc., and it cannot be confirmed in a general environment.

VS1: Very Slightly Included 1

It is a quality with very few inclusions, and it is difficult to check inclusions etc. when a skilled grader is magnified 10 times.

It is difficult for the general public to see it with the naked eye, and even if it is magnified 10 times, it is difficult to recognise inclusions. Therefore, VS1 has a small amount of inclusions, but it is in a class that is evaluated as mild.

Very VS2 Diamond 02

Typical inclusions are small inclusion crystals, small cracks and cracks, and small cloud inclusions (clouds). 

VS class inclusions do not affect the beauty of the stone. It is a clarity grade that is comparable to the highest class, which is extremely excellent in quality that is generally distributed.

VS2: Very Slightly Included 2

It refers to the rating of the second highest evaluation after VS1 even in the evaluation that it contains a very small amount of inclusion.

VS2 diamond 02

It will be a little easier to check inclusions when a skilled grader is magnified 10 times, but it is difficult, and it is very difficult for the general public to recognize inclusions even if they are magnified 10 times. It’s difficult. It is an excellent clarity grade that cannot be confirmed with the naked eye, so it looks the same as the VVS class.

As you can see, grades up to VS2 do not contain inclusions that affect brilliance or are large in size and affect durability. Therefore, Brilliance Plus recommends VS2 or higher as the best grade.

SI1: Slightly Included 1

There are slightly clear inclusions, and the quality is relatively easy to find when a skilled grader magnifies 10 times.

The inclusion characteristics of normal SI1 are not visible to the naked eye unless they are magnified, and it is somewhat difficult for the general public to distinguish inclusions even when magnified 10 times.

SI1 diamond 02

As you can see, many SI1s have subtle differences that are indistinguishable from the higher-ranking clarity grades, and their appearance remains the same. 

Therefore, it is a grade that has both reasonable price and sufficient quality. If you are not particular about VS quality, we recommend it as a quality with high cost performance.

SI2: Slightly Included 2

Even in the evaluation that there is a slightly clear inclusion, it refers to the second-ranked rating after SI1. When magnified 10 times, even the general public can check the inclusions relatively easily.

SI2 diamond 02

Also, in the SI2 class, it is often the case that defects cannot be confirmed when a slightly small diamond of 0.5 ct or less is seen with the naked eye, but inclusions may be rarely seen with the naked eye when the size is larger than that.

I1, I2, I3: Included

Defects such as inclusions and flaws can be easily seen with the naked eye on the face-up, which can seriously affect durability. Large inclusions and numerous inclusions affect the transparency and brilliance of diamonds.

SI2 diamond 01

In addition, most of the products do not come with a certificate because the quality is a guideline for checking defects with the naked eye. Therefore, it is rarely used in engagement rings and is often used in cheap fashion jewellery.

Things to consider when selecting your diamond’s clarity

Looking back at the characteristics of each grade, FL (Flawless) and IF (IF), which are rarely distributed in the general market, can be said to be extremely rare and high quality diamonds that are “undamaged and flawless”.

VVS1, VVS2 and VS1 diamonds are of a quality that is extremely difficult for experts to see with a 10x magnifying glass. Furthermore, even VS2 is at a level that is difficult to distinguish unless the expert carefully observes it.

This may be one of the reasons why the VVS-VS class, which has as few defects as possible, is the most popular engagement ring as a symbol of “pure and innocent”.

The SI class is a grade that can be easily included even by the general public when viewed under 10x magnification, but it can hardly be confirmed with the naked eye and the appearance is almost the same as the high quality.

Inclusion may be visible to the naked eye for diamonds of relatively large SI class size.

Based on the above, considering the balance with other 4C elements, “Choose a rare clarity grade diamond such as VVS or VS?” “Choose a quality with a reasonable SI price and carat or cut accordingly. I would like you to select the diamond that is unique to you by identifying the points that are important to you.

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