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A guide to diamond clarity

Table of contents

Primary Item (H2)

What is diamond clarity?

Before being cut and polished, natural diamonds form deep within the earth under immense heat and pressure. Other minerals become trapped in the diamond crystal as it develops during the diamond formation process. We call these inclusions, and similar flaws or imperfections are also present within lab grown diamonds. In fact, all diamonds have inclusions, but some are more obvious than others. 

Diamond clarity refers to any imperfections or blemishes a diamond may have. The more noticeable are, the lower the clarity grade a diamond is given. 

The Gemological Institute of America (GIA) has recognised diamond clarity as one of three primary measures of diamond quality, the other two being colour and cut. Along with carat weight (diamond size), these form what is known as "the four Cs". When considering the clarity grade you would like for your diamond, it is important to consider carat weight, colour and cut and make a balanced decision that also takes account of your budget and how you want your engagement ring to look.   

You'll want to consider the clarity grade in light of your diamond's carat weight, as inclusions tend to be more visible in larger stones. So, for example, a two-carat diamond with an SI2 clarity grade will tend to have more noticeable inclusions than a one-carat diamond with an SI2 clarity grade.

The diamond clarity scale and chart

The GIA created the diamond clarity scale to standardise the terms used to describe clarity across the jewellery industry worldwide. Whether you're in the UK or the other side of the world, the same clarity grading terminology should be used.

To the naked eye, blemishes and inclusions may be difficult to see. However, a diamond is assessed under 10x magnification for clarity grading by a highly skilled gemologist. The clarity grade awarded to each diamond depends on the size, nature, type, colour, and position of any inclusions or blemishes seen at 10x magnification. 

GIA diamond clarity scale chart
Diamond clarity chart
  • Flawless (FL) - no inclusions or blemishes visible under x10 magnification.
  • Internally flawless (IF) - no inclusions, only very minor surface blemishes visible under x10 magnification.
  • Very, very slightly included (VVS1, VVS2) - minor inclusions that are very difficult to see under x10 magnification.
  • Very slightly included (VS1, VS2) - inclusions range from incredibly difficult to see to fairly easy to see under x10 magnification.
  • Slightly included (SI1, SI2) - inclusions are easily visible under x10 magnification.
  • Included (I1, I2) - inclusions are easy to see without magnification and may impact the sparkle of the diamond.

For those grades with subcategories 1 and 2, the 1 is higher clarity than the 2. 

If a diamond has no imperfections visible to the naked eye, it is described as "eye-clean". As a rule of thumb, this includes all clarity grades from VS2 and above, though sometimes an SI1 diamond may be "eye clean", and conversely, some VS2 diamonds have imperfections that are just about visible to the naked eye.

While blemishes and inclusions are often visible to the naked eye in SI clarity diamonds, they are still too small to impact how much a diamond sparkles. However, at the next clarity grade down, Included (I1 and I2), the inclusions may be large enough to impact how much a diamond sparkles.

What determines diamond clarity

When a diamond grader looks at a diamond under 10x magnification, several factors determine a diamond's clarity grade;

  • Size - the size of the inclusions. More minor inclusions are less likely to be seen with the naked eye, whereas a large inclusion could quickly move the diamond down the clarity scale.
  • Number - how many inclusions and blemishes are visible in the diamond. 
  • Location - the position of the inclusion within the diamond. If the inclusion is on the table, it will likely be more visible. If it has occurred on the edge of the diamond, it can be easier to hide with the setting.
  • Relief - the impact of the colour of the inclusion on the diamond. For example, a dark inclusion will have higher relief than a white inclusion as it's more noticeable.

Together, these four factors determine the clarity grade and, in turn, impact the value of the diamond.

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Different types of diamond inclusions

When looking at diamond clarity, inclusion is a blanket term for all imperfections other than surface blemishes. However, there are many different types of inclusion. Some flaws happen naturally while the diamond is forming, and others can occur during the cutting and polishing process. 

Some of the most common types of inclusions are:

  • Crystals - formed as the diamond does and appear either black or white. Black crystals are much more apparent than white and are seen with the naked eye.
  • Pinpoints - tiny inclusions that look like a minuscule dot under 10x magnification. 
  • Clouds - a cluster of pinpoint inclusions, which in extreme cases, can cause the diamond to look cloudy to the naked eye.
  • Graining - a deformity in the diamond's structure, which can also cause a cloudy appearance in extreme cases. 
  • Twinning wisps - a cluster of clouds, feathers and crystals. Twinning wisps can be either black or white and sometimes have yellow and brown hues.
  • Feathers - minor cracks in the diamond crystal structure, with a feather-like appearance and look either white or dark.
  • Cavity - dents on the surface of a diamond. This type of inclusion can often be seen with the naked eye. You shouldn't purchase a diamond with any cavities on its surface. They can compromise the durability of the diamond. 

How diamond shape affects clarity

Diamonds are available in many different shapes, and some shapes hide inclusions better than others. Most modern diamond shapes have brilliant faceting, which helps to hide imperfections, partly because they sparkle so much! The main exceptions are the step-cut diamond shapes (emerald cut, Asscher cut, and baguette cut diamonds), which lack brilliant faceting and instead create dramatic flashes of light but also reveal inclusions more clearly.

Diamond Shapes Chart edited
Diamond shapes chart
  • Round brilliant cut diamonds - the round is arguably the best shape at hiding inclusions, and for a diamond smaller than one carat, you may find it eye-clean at SI1 clarity. 
  • Princess cut diamonds - this square-modified brilliant cut tends to hide inclusions very well due to the small size of its facets.
  • Cushion cut diamonds - while being brilliant cut, cushions have large facets meaning they hide inclusions less well.
  • Oval cut diamonds - ovals are often cut so that any inclusions are found near the rounded edge, which the setting can then hide.
  • Radiant cut diamonds - radiants are very highly faceted, doing an excellent job of hiding inclusions.
  • Marquise cut diamonds - the marquise has relatively smaller facets and so also hides inclusions well
  • Pear cut diamonds - pears hide inclusions very well due to the rounded and pointed ends of this shape.
  • Emerald cut diamonds - emerald cuts lack brilliant faceting, and with a large table (top facet), inclusions are more visible than in most other cuts, meaning VS1 tends to be the lowest eye-clean clarity grade. 
  • Asscher cut diamonds - a square version of the emerald cut; the Asscher cut also shows inclusions for the same reasons and again requires a clarity grade higher than VS2 in order to be eye clean.

If you're not set on a specific shape, consider one that hides inclusions well. This means you can accept a lower clarity grade and prioritise a bigger carat or higher colour grade if you want. 

Lab grown diamond vs. natural diamond clarity

Lab grown diamonds are assessed and graded for clarity in precisely the same way as mined diamonds. 

As a lab grown diamond goes through its growth process, it is prone to acquiring inclusions and blemishes, just as natural diamonds were when they were formed billions of years ago. However, as the growing process is controlled in laboratory conditions, you tend to find fewer lab grown diamonds with very low clarity grades. Conversely, it is also very rare at this time to find lab grown diamonds with a clarity grade higher than VVS1.

Does diamond clarity matter?

While some people prioritise size (carat weight) over quality, and others will prioritise quality over size, whatever position you take, we recommend taking a balanced view across these three measures of quality: colour, clarity and cut. There seems little point in choosing a flawless diamond if this means your budget won't allow you to have a nice colour grade; likewise, there seems little point in selecting a colourless diamond if it has very visible inclusions.

If it is important that a diamond look flawless to the naked eye (eye clean), then typically, you can achieve this with a VS2 clarity diamond. You may choose to spend more to have a diamond with higher clarity, but it won't look "better" to the naked eye.

If you are happy to have a diamond with very small inclusions that are just about visible to the naked eye, then you will probably be happy to choose an SI1 clarity diamond.

Tips for choosing diamond clarity

There's a lot to consider when purchasing a diamond, so it helps to be as informed as possible when making this special purchase. 

Some tips to think about when considering diamond clarity include:

  • For most people, having a diamond that is flawless to the naked eye is desirable. You don't need to choose the highest clarity grades to achieve this.
  • Some shapes hide inclusions better than others. For most shapes, VS2 clarity will be eye-clean, but for emerald cut, Asscher cut, and baguette cut diamonds, you may need to go higher than this.
  • Larger diamonds have bigger facets than smaller diamonds, making inclusions more visible. For smaller brilliant cut diamonds, SI1 may be eye clean.
  • Check who has graded the diamond. Ideally, it will be certified by the GIA or another reputable gemological authority such as AGS, IGI or HRD). Watch out for uncertified diamonds or diamonds certified by less reputable authorities. The clarity grade may be unreliable.

FAQs

Which diamond clarity is best?

The highest clarity grade is flawless (also known as Loupe Clean). This means the diamond has no inclusions or blemishes visible under 10x magnification. A flawless diamond is very rare and commands a significant price premium. There are lower clarity grades (IF, VVS1 and 2, and VS1 and 2) which are flawless to the naked eye, so they offer great, more affordable alternatives. You can read our guide to flawless vs. internally flawless diamonds to learn more about the difference between these top two clarity grades.

Does clarity affect sparkle?

A misconception is that all inclusions and blemishes affect how a diamond sparkles. However, this is only true for very low clarity grades (Included, I1 and I2) where the inclusions are clearly visible to the naked eye.

Is VS clarity good?

VS refers to very slightly included and is a great choice for a diamond. Both VS1 and VS2 imperfections and blemishes are generally not visible to the naked eye, and these stones are more affordable than FL, IF and VVS1 and VVS2 diamonds.

Summary

When choosing a diamond, many people automatically want to go with the highest possible clarity grade. However, it's important to remember that there are lower grades than Flawless (IF, VVS1 and 2, VS1 and 2), where the imperfections are only visible under 10x magnification. To the naked eye, these look exactly the same as flawless diamonds.

If you have questions about diamond clarity or if we can help you in any other way when it comes to choosing the perfect diamond, we have a team of experts who are more than happy to assist you. Please feel free to get in touch at any time.

Tim Ingle
Together with David Rhode, Tim created Ingle & Rhode to offer a better alternative to the traditional luxury brands. Since 2007, we’ve provided our customers with genuinely ethical engagement rings, wedding rings and fine jewellery – free from conflict diamonds, dirty gold and child labour. With more than 16 years experience in the jewellery industry, Tim has deep expertise in diamonds, gemstones and jewellery design and manufacturing.