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All About Diamond Inclusions
All About Diamond Inclusions

A comprehensive guide about the most common diamond inclusions and what they look like

Karly B. (GIA Gemologist) avatar
Written by Karly B. (GIA Gemologist)
Updated over a week ago

What are Diamond Inclusions?

Diamond inclusions are the little imperfections found inside a diamond. They are tiny marks within that occur during the natural formation of the diamond in the ground or in the machine (yes, lab grown diamonds can have inclusions too). And just like the imperfections found in people, inclusions occur in the vast majority of diamonds.

Not-So-Flawless Diamond ⬆️

Generally speaking, the more visible the inclusions are within a diamond, the lower the clarity grade is going to be. However - and this is important – not all inclusions are created equal. Some are much worse than others - see a list of the worst offenders here. In addition to the type of inclusions, the location is also very important. Is there a big dark crystal smack dab in the center of the stone staring up at you? Or are there some smaller, colorless crystals hanging out along the sides of the stone where they can cleverly be hidden under a prong? Inclusion type and location is not as important in the higher clarity grades (VS1+) since those will all be eye clean.

So, what are the different types of diamond inclusion that you might encounter? Surprise! There’s a long list of them.

The Most Common Types of Inclusions

Most common internal and external diamond inclusions

The inclusions in RED symbolize those imperfections that are found inside the diamond, while the GREEN and BLACK symbols represent marks and blemishes on the outside of the stone. Red and green together mean the inclusion affects both the inside and the outside of the diamond.

These symbols are the key to understanding the diamond grading report plot.

Reading a Diamond Report

Example of GIA report diamond plot

A diamond plot, inside the blue box above, is essentially like a little map of a diamond. It shows where the most prominent inclusions are on the diamond, what type of inclusion it is and how big it is in relation to the rest of the diamond.

Let’s take a closer look at another example:

Diamond plot with inclusions

Every plot will show you the same diamond from two different viewpoints. The plot on the left is the ‘top-down’ view, and its purpose is to show you where to find the inclusions if you were looking at the diamond from above. The right-hand plot is the view from underneath the diamond (i.e. if you popped it out of its ring setting and placed it face down).

Below the plot on the left is the ‘Key to Symbols’, which tells us exactly what type of inclusions can be found in this stone. We already know that RED indicates imperfections inside the stone, while RED and GREEN together means the inclusion is both inside and on the surface of the diamond. The symbols will be ordered based on their prominence (and therefore how much they impact on the clarity grade given).

In the above example we can tell that ‘twinning wisps’ are the most prominent inclusion found in this particular diamond, followed by ‘needles’ and ‘indented naturals’.

"Additional" Diamond Features

One thing to take note of; see if there are any additional comments on the grading report (found on the bottom left-hand corner of the certificate). This is particularly important for natural diamonds in the SI1-2 clarity range.

Additional clouds not shown: This is usually fine! It typically means that there were so many minuscule clouds present in the diamond that it was too tedious to count, map and draw in the symbols on the plot, especially because they aren't impacting the clarity grade of the stone. So instead of putting them all in, they just put a few in the general area to indicate their presence. No biggy!

Clarity grade is based on clouds that are not shown: This is the one to stay away from if you are in the SI clarity range. This means the majority of the diamond is covered in clouds and it will most likely impact the overall look of the stone. These diamonds can be very misleading when you're browsing them online. If you are looking at an SI1 or SI2 that just looks too clean and too good to be true, then it probably is very cloudy material. Don't hesitate to reach out to a gemologist via chat prior to clicking that buy now button for a second opinion!

Do Lab Grown Diamonds Have Inclusions?

Yes! And they are graded on the same clarity scale as natural diamonds: Flawless - I3. Contrary to popular belief, lab grown diamonds do indeed have inclusions but they are just made up of different material. You aren't going to get a garnet crystal inclusion in a lab grown diamond, but it can sometimes happen in a natural stone (and it's soooo cool)! A lot of the inclusions in lab grown diamonds are metallic in nature or non-diamond carbon that gets trapped within the rough while it's forming.

Final Takeaway:

Inclusions in a diamond are not a bad thing! Every diamond is different - every diamond has gone through a different growth process and the inclusions are just one part in showing us how that stone came to be. Think of them as a unique birthmark to your specific diamond, something that no one else has. If you have any specific questions about inclusions or want a final inspection of your top diamond choice, feel free to reach out to our gemologists in chat!

Read more about specific imperfections:

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