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The 4 C’s explained: the fourth C, Clarity

April 13, 2017/ BY Frank van Poorten

The 4th and final of the four c’s we discuss in this series is the clarity of a diamond. A natural diamond is rarely without imperfections. It is a hallmark of Mother Nature to show that nothing is perfect. To evaluate a diamond’s clarity, we us a 10x magnifying glass. This is the tool everyone uses to have unity in the outcome. Under a microscope, you will always see impurities.

Types of impurities in diamonds

Imperfections in a diamond can have various causes. Generally, the impurities are black spots, air inclusions, fractures or natural roughnesses:

  • Black spots consist of carbon that is not fully crystallized. In a diamond these look like dots, spots, feathers or dashes.
  • Air inclusions are small bubbles or air chambers inside the diamond. A diamond is a natural product and something can happen during the formation of it. If there’s a small opening during the creation, a bit of air can sneak into the diamond. When the opening is filled, the tiny air bubble is trapped in the diamond forever.
  • Fractures in a diamond arise as well during the formation. A diamond is created under very high pressure; this pressure can deform the diamond. The deformation can cause small fractures in the diamond which can be seen as minor impurities.
  • Natural roughnesses are ‘raw’ pieces on a diamond. A grinder or diamond cutter can cut the diamond very efficient or too thrifty. He does this because he doesn’t want to lose too much of the diamond during the grinding or cutting process. When a diamond worker cuts the diamond too parsimonious, small pieces of roughness can remain on the diamond. This is visible on the diamond as a small notch or a slippery spot. Often this is at the girdle (the diamond’s widest part) and at the lower part of the adjacent facets.

diamond facets

Gradations of clarity in diamonds

Besides the different types of impurities, the quality of the clarity depends primarily on the size of the imperfections. This size determines the diamond’s clarity label. The sizes of the imperfections are listed as follows, from pure to impure:









Completely pure diamond, free of impurities. These kind of diamonds are very rare
 Clarity VSS     VVS 1&2


Very, very small imperfections. Even with a 10x magnifying loupe you can barely see them.
 Clarity VS1 VS 1&2


Very small imperfections. If you look closely through a 10x or more magnifying loupe, you’ll be able to see them.
 Clarity SI SI 1&2


Small impurities that can be seen with a 10x magnifying glass. These imperfections however, don’t affect the diamond’s sparkle.
 Clarity P1 Pique 1


Small impurities which are visible under a magnifying glass. If you look closely, you can perhaps even see them without a magnifier. These impurities nevertheless do little off the diamond’s sparkle.
 Clarity P2 Pique 2


Small impurities which are visible to the naked eye


Impurities in the cut

Impurities in the diamonds are the least affecting factor in the 4 C’s. Up until the SI, imperfections are not visible to the naked eye. However, a pique diamond can be placed into a piece of jewelry in such a way, that the imperfections in this diamond aren’t visible either. A good diamond cutter will always consider the placement of the impurity during the grinding process. If a black spot appears in the collet (the bottom tip), it can reflect 8 to 24 times more. In that case, a tiny speck can look like a huge horrifying impurity. Exactly for this reason it is so important to have a diamond that was cut by a professional.

The cut of the diamond affects the visibility of imperfections as well. Brilliant-cut diamonds, such as the Brilliant, Princess, Oval, Pear, Marquise and Heart shape can more easily hide minor impurities. This is in contrast to other grindings, such as the Emerald, Asscher and Baguette cut. That’s because the latter cuts have a larger table and impurities show grim.

all diamond cuts

Tips for buying a diamond

If you really want a diamond without impurities, you should take a VVS diamond or higher. Note however that only a small 10% of all diamonds that are found have this gradation.

The most popular purity is VS. These stones appear pure to the naked eye and the impurity can only be found with a loupe. About 50% of the stones that are found are within this category. This also makes them instantly much more affordable than VVS or higher.

After VS, there’s the SI. This category has impurities that are too small to be seen easily without a magnifier. People often choose SI diamonds, so they can afford a higher carat, purer color or better cutting shape. By downgrading the clarity, you can often upgrade on one of the other C’s.

The bigger the stone, the more important the diamond’s clarity is. This is because it is in fact easier to spot impurities on a big stone. For stones larger than two carats, I encourage you to take a diamond with a purity of at least SI. At large pique diamonds, spots can often be visible.

diamond setting in a ring

Want to know more about the 4 C’s?

Do you want to know more about the 4 C’s of diamond evaluation? Then you may want to read the articles about the carat, cut and color or book a free tour through our diamond factory. Our experienced guides would love to tell you everything about the 4 C’s as well.

> De 4 C’s highlighted: the first C, Carat
> De 4 C’s highlighted: the second C, Cut
> De 4 C’s highlighted: the third C, Color


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