What are Diamond Inclusions and Blemishes?

13 March 2020

What are Diamond Inclusions and Blemishes?

Diamond jewellery is an investment and the value of that investment is what allows a piece to stand the test of time. To be valuable enough to become a treasured item that is passed down through generations. This investment value will always be secured through exceptional purity and clarity that cements the stone rarity. This is the legacy that will be made with exceptional stones that go beyond the norms of their grade. They are the exception to the expected.

How can you secure stones of exceptional clarity? Firstly, you will have to know what you’re looking for!

What is the difference between an inclusion and a blemish?

Blemishes are scratches, chips or damage to the surface of the diamond whereas, inclusions are found within the diamond itself.

What are the different types of inclusions?

It is always hard to locate an inclusion or blemish within a diamond especially, when you have no idea what you’re looking for! To get a better idea of the types of inclusions that can present themselves, the GIA have put together an informative series of images. Not only are there great descriptions of the different types but also some close-up images that will give you a great idea of what the inclusions and blemishes look like under 10x magnification.



What are the worst types of inclusion?

Inclusions come in all different shapes, sizes, colours and locations so it is hard to pin point exactly which ones are the worst.

Whilst considered one of the hardest substances on earth, even a diamond can be broken, cracked or chipped. These are the worst types of inclusions and blemishes as they will impact the physical integrity of the stone. Whilst stones with these inclusions will be a lot cheaper, it is recommended to stay away from them at all costs.

Whilst most inclusions may not impact the physical integrity of the stone, they can severely impact the appearance. Listed are some of the worst examples of these forms of inclusion:


An angular opening on the diamond that is created when either a feather breaks away from the diamond or if a surface reaching crystal drops out or is forced out during polishing. Put simply, cavities are a hole in the diamonds surface. Usually only diamonds of a lower clarity grade will have cavities however, you should always look out for the odd VS2 diamond that has one as well. Cavities have a tendency to collect oil and dirt that may make the area look dark and dull.



Drill Holes:

Another form of inclusion to look out for are drill holes that create a surface reaching feather. Used as an access point to bleach an inclusion, it will be used to decrease an existing inclusions visibility in a diamond. This form of inclusion will be clearly labelled on the GIA certificate and visible under 10x magnification however, it will not be visible to the naked eye. Whilst this form of inclusion may not affect the appearance of the diamond it will greatly reduce the value of the stone.


Indented Natural:

An indented natural is a small portion of the diamond that dips below the surface of the stone. This rough area remains unpolished as it cannot be reached during the polishing process. Normally located around the girdle, it can often collect dirt and oil making the appearance slightly darker than the rest of the diamonds surface. This form of inclusion is usually not recut as the loss in carat weight will outweigh the benefits of removing the inclusion



A simple way of understanding crystals is to think of them as mini diamonds and mineral deposits trapped within a larger stone. They can come in all sorts of shapes, colours and sizes but the golden rule with crystal inclusions is to ensure that they are white. This means that they are less obvious to the naked eye and 10x magnification. The worst type of crystal inclusion is a carbon black spot.

        Carbon black spots: 

Blacks spots are a type of natural crystal created during the formation of the diamond when small dots of carbon are not crystallised. They are a lot more prominent in the diamond than other white inclusions so they will dramatically reduce the value and real-life appearance of the diamond.

Be careful as the difference between a white and black crystal will not be indicated on the GIA certificate!

What is the table of the diamond? Why is it important?

No matter what cut the diamond is, the table will be the largest facet. It is located at the very top of the stone and is essential in determining the diamonds brilliance and light performance. This is important as the table allows light to enter the diamond, reflect amongst the facets of the stone and then be reflected back to the observer’s eye.

Considered the ‘face’ of the diamond, the table is the worst location for any blemishes or inclusions. This is mainly because when an observer looks at a diamond, they are most likely to focus on the centre of the stone rather than its sides. This is especially important to keep in mind with low clarity grade diamonds as the inclusions are more likely to be visible to the naked eye.

Top Tips for hiding inclusions:

Even if a diamond has noticeable inclusions, there are some tricks that experts use to minimise their appearance within the stone.

-          Location:

Ensure any inclusions are located away from the table of the diamond. Optimally all inclusions will be placed around the sides of the stone.

-          Prongs or Setting:

You should always ask an expert what the best way to set your diamond is so that you can optimise shine, brilliance and light performance however, if the inclusions are located to the side of the diamond, it can be possible to cover them with the prongs or setting of the ring.

-          Avoid Carbon Black Spots:

Avoid carbon black spots at all costs if you want the face-up appearance of the diamond to look as eye clean as possible. Any black spots are very obvious to the naked eye when compared to white cavities.

What inclusions are not shown on the GIA report?

Whilst the majority of inclusions are reported by the GIA and plotted on a diagram of the diamond, there are some instances in which the inclusions are not shown.

  • The length, depth and width of the inclusion will not be shown or accurately described on the GIA report.
  • The colour of the inclusion will not be shown. This means that you cannot use the GIA certificate to determine whether the inclusion is a white crystal or carbon black spot.
  • The GIA report will not show how the inclusion is reflected around the different facets of the stones
  • Any inclusions that are too small to plot will not be recorded on the diamond diagram but instead listed under ‘additional comments’. This is important to remember as a cluster of pinpoint inclusions can make the diamond look cloudy or milky. This is usually only important in diamonds with a clarity grade of VS2 or below.

These points of difference between the GIA report and the diamond are most important to consider when dealing with stones with a clarity grade of VS2 or below. For more information on how to read and identify inclusions that may not be listed on the GIA report, check out our blog post on ‘Defining Clarity’ here:

At Bee’s Diamonds, we emphasise the importance of education. Educating the client on exactly what they are buying. This is done by not only showing the client how to use a loupe but showing them how to identify the inclusions with in the stone. Contact our specialists to learn more about diamonds and their inclusions.

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