Diamond Inclusion Types – The Complete List with Explanations

The diamond’s magnificent sparkle can easily seduce the viewer. Cut in ideal proportions, the dance of light the gem exhibits can prove to be one of the most spellbinding rarities in the world!

Diamond inclusion types

Although it’s not just about the cut as diamond clarity also plays a big role in the visual and light performance of the gem. Without inclusions and other styles of flaws, there’s nothing stopping the light from igniting the diamond – making it what seems like a tiny star glistening on your finger and the ultimate spectacle that connote timeless commitment!

We meet in this space to get to know the imperfection of diamonds and to eventually discover its perfection. Just like us, they’re naturally born with impurities, but we can at least try to get as close to absolute purity as possible!

flawless round cut diamond

 

Rest assured that after reading this post, you’ll have a better understanding on every inclusion type that you might stumble upon in your diamond grading report.

And at the end of the day, if knowing of the diamond inclusions is your means to compromise on the quality and value of the gem, then you’ve come to the right place. Because aside from providing the real score on diamonds, my other objective is to give you the maximum value for your money! Sounds good?


Let’s Begin with a Quick Primer on Diamond Inclusions:


It’s easy to be mesmerized with the diamond’s dance of light, but if the gem bears big, dark inclusions, there’s not much spectacle to show. Plus, the durability of the diamond could be at risk.

The clarity grade labeled for each diamond is given depending on the size, type, color, location, and amount of inclusions.

Here are the types of flaws found inside a diamond:

Complete list of diamond inclusion types in GIA a plotting diagram  

With plotting diagrams like the image on the right, it’s easier to understand the kinds of inclusions indicated in a diamond’s grading report. Though there are still general rules that you have to bear in mind. More on this later!

For now, let’s skim through this comprehensive list of the most common diamond inclusion types and clarity characteristics with examples and explanations.

What kinds of inclusions are visible to the naked eye and which poses a serious concern?

Take a closer look!


Laser drill hole diamond inclusion

Laser Drill Hole in a diamond

When enlarged, you can imagine it to look something like this.

It’s not as big as it sounds. In fact, most laser drill holes aren’t visible to the naked eye.

The process is quite simple. The cutter uses a laser to drill a microscopic tunnel into a diamond and remove a black internal inclusion. In the clarity plot, the laser drill hole will be indicated by a red point surrounded by a green circle.

If the drill hole in the surface of the gem isn’t evident, you’ll see “Internal laser drilling is present” in the comments section.

It’s advised for sellers to disclose any laser drilling as it can severely affect the price of the gem.


crystal diamond inclusion

Crystals are dubbed as “baby diamonds” because they are essentially bits of diamonds or mineral deposits that are trapped inside a larger diamond when it was formed.

The crystal inclusion is shown as a simple red circle in a diamond clarity plot. It comes in various shapes and colors which is dependent on the specific mineral that is trapped within the gem.

Example of diamonds with white crystal inclusions from James Allen:

1.30 CARAT K-SI2 EXCELLENT CUT ROUND DIAMOND with white crystal inclusion 0.71 CARAT J-I1 EXCELLENT CUT ROUND DIAMOND with white crystal inclusion

Reddish crystal inclusions are usually garnets, and on rare occasions, you can also see a greenish inclusion also known as Peridot.

The golden rule for crystal inclusions is to only choose the white ones. If they aren’t too big, there’s a good chance that the crystal won’t be visible to the naked eye. Furthermore, white crystal inclusions under the crown facets are more difficult to detect than say, a white crystal inclusion directly under the middle of the table. (Learn more about the diamond anatomy here!)

 

Black crystal inclusions usually consist of carbon or graphite:

1.30 CARAT K-SI2 EXCELLENT CUT ROUND DIAMOND with black crystak inclusion 0.71 CARAT I-I1 EXCELLENT CUT ROUND DIAMOND with black crystal inclusion

Obviously, this refers to crystal inclusions in SI1 or SI2 diamonds. In VS2 diamonds (and above) graded by GIA and AGS, you won’t have to worry about any visibility issues. Crystal inclusions in an eye clean diamond are usually too small to pose a serious durability risk.

Dark crystals, however, can usually be perceived by the naked eye, particularly if it is the grade-setting inclusion in a SI1 or SI2 diamond. This is what you should definitely avoid!


needle diamond inclusion

This one is a type of crystal along with clouds and pinpoints. As its name suggests, a needle is a long thin crystal inclusion that is usually white or translucent.

Here’s a noticeable needle in a diamond:

needle inclusion in diamond

Because of extreme pressure when it was formed, a crystal turns into a needle shape instead of the typical circle. Such flaws are usually invisible to the naked eye. But if they do appear in clusters, that’s a different story!


pinpoint diamond inclusion

pinpoint inclusion in diamond

Now, this type of inclusion is the most common. Pinpoints usually appear as white dots that look like pinpoints of light when viewed under 20x magnification or higher.

Some pinpoints also come in gray or black. They’re pretty difficult to locate, so you won’t see them often on the plotting diagram of a diamond grading report.

Instead, you might see the remark “pinpoints not shown” in the comments section.

 

A single pinpoint inclusion doesn’t really affect the diamond clarity, but if there’s three or more in one area, a cloud is then formed.


cloud diamond inclusion

cloud inclusion in 0.90 CARAT G-SI2 EXCELLENT CUT ROUND DIAMOND

The visible white cloud in this excellent cut diamond makes it a SI2 gem.

You may have noticed that inclusion names are short and punchy. It’s a great way to remember what they are upon first glance.

The “cloud” is named as such because of its white color and hazy appearance. But if you look closer, it’s actually a cluster of pinpoints inside your gem!

You’ll know there’s a cloud inclusion in your diamond if you see a circle made up of small red dots or pinpoints on the diamond grading report.

If they’re tiny and subtle, clouds don’t really pose a threat. But if they’re too big, they can make the gem look hazy and affect its light performance.


twinning wisp diamond inclusion

twinning wisp in round 0.92 carat diamond

Round 0.92 carat diamond with twinning wisps.

Imagine stretch marks, but on a gem. That’s what twinning wisps look like! It’s basically the twisting of the crystal plane that appears as a wispy line.

A twinning wisp is formed as a result of growth defects in a diamond’s crystal structure. It is said that during the formation process, the diamond must have stopped developing due to poor conditions, and as it resumed (even for a thousand years later), the twinning wisps were formed.

It may look like another kind of inclusion, but it’s actually a series of crystals, clouds, feathers, and pinpoints. It’s usually seen in fancy shape diamonds because they are often styled from twinned crystals.


knot diamond inclusion

knot inclusion in diamond

Magnified image of a knot inclusion in a diamond.

A crystal inclusion is considered a knot if it reaches the polished surface of the diamond. With the right lighting and magnification, you’ll be able to see where the knot and the surface meet.

Since it’s near the exterior, it could also give the impression that the diamond has a raised area on one of the facets, and it can usually be seen with bare eyes. Meaning, your diamond won’t be eye clean. What’s more is that knots can affect the durability of the gem in the long run.

So, when you see the diamond’s grading report bearing this inclusion, you know what to do!


feather diamond inclusion

feather inclusion in 0.90 CARAT G-SI2 EXCELLENT CUT ROUND DIAMOND

Feather Inclusions in a SI2 Diamond

Nope, there isn’t any real life feather trapped in a diamond. Its name simply suggests its resemblance to a bird feather. The form can be pretty clear when viewed under high magnification, but most of the time it looks transparent. Basically, it’s a just a tiny crack inside the gem.

Take note that even though these are minute fractures, they can also cause durability issues if they’re placed near the girdle area or cavities. When looking at the plotting diagram, you’ll know there’s a feather if there are hash marks or red lines. Read more about feather inclusions here!


chip diamond inclusion

chip inclusion in diamond

Now, don’t be confused with the chip inclusion and the “diamond chip” – which is a minute diamond.

What the chip inclusion really looks like is a small opening near the edges, facet junctions, or the surface of the gem. It’s usually caused by accidental bumps or wear and tear.

Chips aren’t big of a deal because they can be removed by re-cutting and polishing. Although wider chips may require major re-cutting that could result to carat weight loss.


cavity diamond inclusion

cavity inclusion in 1.00 CARAT G-I1 EXCELLENT CUT ROUND DIAMOND

Cavity in the upper right of the table facet.

And you know how cavities in our teeth turn darker when not treated? It’s the same with diamonds. When oils and dirt become trapped in a large diamond cavity – that could be a problem.

However, most cavities are usually small and will only be noticeable under 10x magnification. They are formed when an internal inclusion falls out of its pocket during polishing.

So yeah, a cavity in a diamond is what it seems – a hole, indentation, or deep opening within the crystal structure of the diamond. They can also be found at the girdle, table, crown, and pavilion.

You won’t really notice a cavity near the crown or girdle, but if it’s close to the pavilion or under the table, the effect in clarity will be much greater.


bruise diamond inclusion

We’re all familiar with bruises. And since diamonds are sometimes more fragile than our skin, it’s not surprising that they, too, experience bruises.

This type of inclusion is from a sharp blow to the diamond’s surface that extends inside the gem, causing small feather inclusions. Bruises are usually found in the diamond crown, but they can appear in different locations and sizes.

bruise inclusion in diamond

Most of the time, cutters are at fault for this inclusion. In the hopes of finishing sooner, they may use the polishing wheel with greater impact. You might mistake a bruise for a blemish, but since it vines below the surface of the gem, it is then labeled as an inclusion.


etch channel diamond inclusion

The etch channel is sometimes mixed up with the laser drill hole, but aside from appearing like a hollow tunnel, they’re also found as parallel lines or worm-like channels.

There’s a debate whether etch channels are man-made or natural. But for scientists, they’re as natural as they can get! Formed during the diamond’s journey from Earth’s mantle to the surface, etch channels are left as scars by intense heat.

etch channel inclusion in diamond

Just like drill holes, dirt can get trapped inside the channels and can make cleaning difficult, so it’s best to avoid such inclusions that are placed on the pavilion part of the diamond.


natural diamond inclusion

It’s true that flaws make things unique. Sometimes imperfections are left as is because they contribute to the beauty of the gem. Seeing a natural is not to worry about. It’s simply a part of the original skin of the diamond that was left on when it was cut. They’re usually found along the girdle edge of a diamond.

natural inclusion in diamond

Its name rings true as it’s considered as a very common inclusion since it’s treated as a cutter’s guideline for getting the maximum possible diameter of the stone out of the rough.

As a matter of fact, 20 years ago, naturals were found on the four corners of a round diamond as proof to the owner of the factory that the cutter hadn’t removed any unnecessary rough.


indented natural diamond inclusion

indented natural inclusion in diamondThen there’s “indented natural” which is a “natural” that indents slightly inside the surface of the diamond. Same as the natural, it’s also located along the girdle edge of the gem and can be difficult to find.

Some people who don’t take time evaluating the diamond confuse it with chips. If the weight has to be retained, the cutter has no choice but to leave an indented natural in the diamond.


What Type of Inclusion Should I Avoid?


Every inclusion infuses character to the gem. Diamonds are born with it, so there’s actually some kind of beauty with their natural flaws. But if you have to avoid an inclusion, it should be chips and dark crystals.

Chips are easily seen and once the surface of the diamond has been damaged, it would probably chip again. Aside from affecting the visual appeal of the diamond, it also weakens its internal form. While black dots or carbon crystals are the most annoying flaws you’ll see because they’re simply unflattering to the gem.

 

Take these I1-clarity diamonds bearing black spots for example:

black crystal inclusions in I1 clarity james allen


Tips on Reading the Diamond Clarity Plot


Remember that the first inclusion on the grading plot is the grade-setting inclusion. It’s mainly responsible for the clarity grade. Also take note that internal flaws are in red color and external flaws are in green.

Most of the time, GIA and AGS only issue clarity plots for diamonds above one carat. So, don’t be surprised if a diamond under one carat doesn’t bear a clarity plot in its grading report.

Looking at a diamond clarity plot is a great way to have a more accurate information about the diamond’s inclusions. However, the grading certificate is not enough.

 

Just have a look at these clarity plots that I found at James Allen:

SI2 diamond with black crystal inclusion plotting diagram

Both diamonds are SI2 diamonds that have crystal inclusions under the table. As far as the crystal inclusions under the table are concerned they look pretty similar. But, let’s have a look at what both diamonds really look like:

1.30 CARAT K-SI2 EXCELLENT CUT ROUND DIAMOND with black crystak inclusion 1.30 CARAT K-SI2 EXCELLENT CUT ROUND DIAMOND with white crystal inclusion

As you can see, the diamond on the left has a stark, black crystal inclusion. While the diamond on the right only has a white crystal inclusion which would be more difficult to detect in the real diamond.

Admittedly in this case, both diamonds would not be eye clean, but the gem on the right would still be a much better choice than the one on the left.

Also, if you would click the diamond on the left and look at the clarity plot, you will see that it’s only that one, dark crystal inclusion under the table that will be visible to the naked eye. Even though there are so many other tiny crystals and clouds in the diamond. This is why you should never buy a diamond blindly!


Viewing Diamond Inclusions in 10x Magnification


james-allen-20x-magnification

Online diamond shops have revolutionized how we shop for diamonds today. You don’t just have to rely on GIA grading reports anymore, but you can also view the exact gem in 360-degree high definition videos. And for clarity features, there’s imagery up to 40x magnification.

The top shops that have changed jewelry e-commerce are Whiteflash, Brian Gavin, and James Allen. For colored diamonds, it’s Leibish & Co.

 


Final Thoughts about Diamond inclusions


By now, you already know how important it is to not buy diamonds blindly. Given these different kinds of inclusions, a diamond display technology is indeed a must! Seeing that a diamond is eye clean and within the VS range no matter what inclusions it possess is your key to almost perfection.

Take this rule to heart and you’ll see that you don’t really need a flawless diamond. Because after all, it’s the minute flaws that makes a gem uniquely beautiful.

If you have any question about a particular inclusion in a diamond, I will be more than happy to help you out. Just leave a comment below or email me here!

 

Diamond Inclusion Types – The Complete List with Explanations
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About 

Sebastian Naturski loves to write about diamonds and share his knowledge with his readers.
When he is not working on his website he is studying law at Humboldt University of Berlin.
He has taken part in several international law competitions and likes to broaden his horizons.
His other big passion are languages. He is fluent in German, English, Polish and Japanese and got basic skills in French and Spanish as well.