Everyone notices the freckles that some people have as opposed to the conventional birthmarks of others because they are very unique. They are considered to be beautiful and, in some quarters, sexy. The same cannot, however, be said about certain birthmarks.

In the world of diamonds, birthmarks are considered imperfections that are found on diamonds by reason of the fact that they are formed from deep within the earth’s surface. These imperfections make the diamond unique and one of a kind because none of them are the same.

There are many types of inclusions that we will see below, for instance, this is is an SI2 diamond on Blue Nile that has 6 types of inclusions!! Covering most of its table! And here is a screenshot for its GIA certificate (From the Clarity section):

On the other hand, look at this diamond on James Allen, and here is its clarity section from the GIA certificate:

GIA 1.08

A lot of difference right? That’s why YOU MUST see the certificate before making a purchase.

We see here why it’s important to trust high-reliable certification labs like GIA, and only from trusted vendors like James Allen, Blue Nile or Whiteflash when you’re considering getting a diamond.

Freckles, however, would be considered blemishes here because they are imperfections on the outside as opposed to inclusions which are inside. But are all inclusions the same? Which are worst and should avoid? Which are “okay” to have? And how they affect diamond total clarity?

What are Diamond Inclusions?

Diamonds are created under tremendous pressure & heat under more than 100 miles on earth, 2000 Fahrenheit and more than 70000 pounds per inch square pressure will definitely leave some imperfections on the diamonds surface, these imperfections are called diamonds inclusions.

Diamonds with no inclusions are very rare, rare to the level that most jewelers (not only customers) live their life without seeing one.

JamesAllen, the biggest online store for diamonds which has more than 300000 diamonds on their website, has less than 100 flawless diamonds (diamonds without any inclusions) as you can see here.

Read: What is the Best Diamond Clarity to Get?

Diamond Inclusion

What are Inclusions Types?

All diamonds (except flawless) have inclusions, some of them are clearly visible to naked-eye (these are worse of course), while most of them are not, unless you check the diamond with a loupe.

This image for example, found on JamesAllen for around 5k (sold now), has all inclusions types you may ever see, more to come shortly.

Bearing in mind that diamonds possess birthmarks that are unique to each one, inclusions are of different types, let’s take a look at the most popular inclusion types found on diamonds, which are worse and should be avoided:

1. Crystals

Crystals are simply put a collection of small diamonds or minerals trapped inside a larger one during formation. Some of them are invisible to an unaided eye. They are many types, white crystals, black, colored, or transparent (colorless). It is easy for the white to blend in but you may have a hard time with the black & transparent.

The more the color, the better you should avoid since it will have more effect on diamond brilliance, as a rule of thumb, you should try to avoid any colored crystal inclusion.

Diamond Sparkle James Allen

2. Needle

Needle inclusion in diamondWhen diamonds are formed, the pressure could make crystals turn into a needle-like shapes. They are usually white in color or transparent.

Needle usually are seen under magnification as it’s not easy to detect them with naked eye, if you saw the needle looks “clustery”, you better skip that diamond.

3. Pinpoint

These are inclusions that appear as white dots and are not really visible, they can be either white or black crystals, they are very tiny and don’t have much effect on diamond clarity.

4. Clouds

Clouds are some times referred to group (cluster) of pinpoints or crystals in general, it’s called cloud when these pinpoints are very close to each other so that they form a “cloud” of inclusions

They are not usually visible but if they are bigger they could affect the gem’s light performance.Diamond Cloud

5. Twinning Wisp

This inclusion looks like stretch marks but on a gem, it’s a bit different from the cloud that it’s a series rather than a group of pinpoints/crystals, it even can be a series of cloud as well, and it is said to be caused by a pause during formation, the resumption of which leaves the gem dented.

Usually the twinning wisps are found in fancy shape diamonds, if the wisp is large, look for another diamond.

6. Knot

Knot Inclusion in DiamondThese are inclusions that have reached the surface area of the gem. They can actually be seen with naked eyes and they affect the durability of the gem, knot inclusions extend to the surface after fashioning.

Blue Nile Ring 2

7. Feather

Feather inclusion in diamondThis inclusion is called feather because of its shape. It is basically a crack in the inside of a gem. It causes durability issues if placed close to the girdle area, often white and feathery in appearance.

The problem with feather inclusions is not only that they affect clarity, but if they are near the diamond surface, it might affect diamond durability as well, better to be avoided if large or reached the surface.

8. Chip

This inclusion is an opening on the edge or surface of the gem. This happens mostly from wear and tear. Chips can be corrected by cutting and reshaping but where they are considerably large, cutting could affect the carat weight of the gem.

9. Cavity

Cavity Inclusion in diamondThis is an angular opening or a hole in the center of a gem, such inclusions are created when part of a feather breaks away, and sometimes when a crystal that is surface reaching drops out, they are however not really noticeable.

10. Bruise

This occurs from a blow to the surface of the gem which extends inside. Diamonds are quite fragile hence this inclusion.

11. Bearding

These inclusions are called bearding because they really look like hair (beard hair), they often occur in the cutting phase. While it’s not much of important if it’s tiny, but if a girdle is heavily bearded, its appearance will look a grey and fuzzy fringe, almost as if it has been scratched

12. Indented Natural

Indented Natural is a portion of the rough diamond’s original surface, it can’t be fixed with the polish because it dips below a polished diamond’s surface.

Indented Natural

So are all inclusions are bad? Not necessarily, actually these inclusions help gemologists separate natural diamonds from synthetics diamonds, as well as identify individual gems and grade it accordingly.

The diamond inclusion or clarity chart is basically a grading of diamonds according to their inclusions. This chart was established by Richard Liddicoat and it’s what we know it today as the GIA Clarity Grading System. later in this post we will take a quick look on the 6 clarity grades.

Inclusions Characteristics that Affect Diamonds

Sometimes gems with inclusions are purchased because the inclusions are the source of beauty in the gem. Most inclusions, however, affect the gem’s clarity or grading, however this could depend on a number of factors:


When gems are graded, the grading comes after the gem has been inspected under 10x magnification. The reason is that the inclusions are mostly visible under magnification. The size of the inclusion impacts greatly on the grading. Where the inclusion is large, the gem is graded lower than where the inclusion is little, and this makes sense, that’s why an eye-clean diamond (VS1 for example) will not have any inclusions that you can see, while the same exact inclusions (if happened) with a larger size will probably make the same diamond an SI1.


When the inclusions in a gem are numerous, it affects the grading as it will make the gem very unattractive.


Diamond TableWhere the inclusion is situated in the gem goes a long way in grading. If it is at the table facet, it is most visible and generally affects how the gem is seen since the table is the like the mirror of the gem and it is the first place considered when looking at a gem. Where it is at the girdle, it is rarely visible. Where the inclusion is at the culet, it reduces the value of the gem because such inclusions can reflect throughout the gem, this image explains how each location affect the overall clarity.


When inclusion is closer to the color of the gem, it lowers its relief. Therefore inclusions like crystal that are translucent or white have less impact on the gem than inclusions that are dark.


Different types of inclusions that we mentioned previously have different degrees of impact on a gem’s clarity and grading. For example, pinpoints have a lesser impact because they are barely visible even under 10x magnification. Other inclusions like feathers can have a greater impact as it could cause gems to crack.

Do All Inclusions Have the Same Weight / Effect?

We’ve seen above the most inclusion types that might affect clarity. But a good question is:

Do all inclusions have the same effect on diamonds? Or Some inclusions are worse than others?

The latter question is the right one of course, not all inclusions are the same, and they don’t have equal effect on diamonds, some of them are very bad, and in some cases, a diamond graded as SI1 or SI2 might be a VVS if it doesn’t have a specific inclusion (depends on type and location).

Look at these two diamonds on Blue Nile:

1- 1.00 Round, F Color, SI1.

2- 1.01 Round, I Color, SI1.

Both diamonds are SI1 clarity-graded, but if you look at the GIA certificate for both of them, and exactly on the Clarity Characteristics section (please note that this section is only available for diamonds over one carat), you can see a huge difference in number of inclusions found on each one.

Diamond Clarity Difference on GIA

The first one has around 9 inclusions on its crown, and this is “relatively” a low number of inclusions, yet it was graded as SI1 not higher! Will see shortly why.

The second one has tons of inclusions all over the its crown! And it was graded SI1, same as the first one.

By the way, both of them have excellent polish!

Why is this?

That’s because not all inclusions are equal, some inclusions can’t be that harmful to the diamond brilliance, but others leave a huge impact on diamond ability to reflect light, and they are considered much worse than others.

Which Are the Worst Inclusion Types to Avoid?

We’ve seen above the different types of inclusions, and at this point we know that they have different effect on the clarity grade, and on diamond ability to reflect light generally.

In order of worseness level of inclusions, here are the worst inclusions that you need to do your best to avoid:

1- Black Carbon Spots / Crystals:

These are the worst inclusions you don’t want in your diamond, black spots literally block the light from going through the diamond when it gets to the spot location.

They look like small pieces of crushed tiny pepper and should be avoided even if the spot is underneath the stone (which will be covered under the setting), note that we are only talking about black crystals and not all of them, only black.

2- Top / Center-Located Inclusions:

While this is not a specific type, but any notable inclusion in the top or center of the diamond will be very harmful to your diamond.

Look at this diamond on James Allen and see the inclusion location on the middle, this location is a killer one for any inclusion to “destroy” the diamond brilliance, when you look for a diamond, try your best to get a clean surface from the top.

James Allen Diamond with inclusion in center

This diamond has many other visible inclusions as well, but we wanted to highlight how important the location of an inclusion is.

3- Long Fracture / Crack:

Have you ever imagined that someone can break a diamond? What about the 10/10 grade of strength on Mohs Scale?

If a diamond has a short needle, that’s not a big issue, but if the needle / crack is too long, and it runs all the way through the diamond, and the diamond slammed against a wall so hard, it “might” split the diamond into halves, but this is very rare and totally depends on the crack depth and length.

Look at this diamond (at 6 o’clock), you can clearly see a long crack, it’s not that long to break the diamond, but this is the type of inclusions you want to avoid.

4- Clouds:

This is very important, you can ignore very small clouds, but if a cloud is covering a good portion of the diamond surface, the diamond will look hazy and milky, this will affect its look, and more importantly, its brilliance.

Look at this diamond in 360-degree on Blue Nile, here is a screenshot of its clarity section on its GIA certificate as well.

It’s not only that the cloud covers a lot of space on the diamond surface, what’s worse is the location, right in the middle of the crown.

Cloud on Center of a Diamond

Diamond Clarity Grades

One of the most important factors in any diamond is the clarity, Clarity is one the 4Cs of diamonds, and it’s graded into 6 categories based on the cleanness of a diamond.

We’ve covered the detailed grades with real images in our Clarity article, but in short here, these grades are:


Diamonds graded FL have no inclusions or blemishes visible to the eye at 10x magnification. These diamonds are extremely rare and are very expensive. Only 1 in 5000 diamonds are rated flawless.

Internally Flawless

These are diamonds that do not have inclusions but only blemishes. These blemishes are barely visible under 10x magnification. Only about 3% of diamonds are ever rated IF and if put side by side with FL, they are quite similar to the unskilled eye.

Very Very Slightly Included

Inclusions in diamonds here are difficult to see at 10x magnification. For VVS1, inclusions can only be seen from the pavilion while for VVS2 diamonds, their inclusions can only be seen from the crown.

For both, the inclusions are of course not visible to the naked eye and look similar to the flawless grades. These diamonds have clarity and are equally expensive.

Very Slightly Included

Inclusions in gems so graded are very visible under 10x magnification but are described as minor. They are not however visible to the naked eye. Their slight inclusions do not affect clarity or transparency. These gems are divided into VSI1 and VSI2.

Slightly Included

Diamonds of this grade have inclusions that are visible under 10x magnification. Some of these inclusions can be visible to the naked eye when observed under close inspection. They are divided into SI1 and SI2 gems (EGL introduced SI3, but it’s not internationally adopted).


Diamonds of this grade have inclusions that are obvious under 10x magnification. The inclusions are always visible to the naked eye and sometimes may affect the durability of the gem. They also reduce transparency and the brilliance of the gem. They are divided into I1 through I3.

How Inclusion Location Affects Clarity Grade?

Look again at the image above, and particularly on diamond 1 lower girdle facet (bottom right at 5 o’clock), you will see there is a small inclusion there, and on the keys section, it will tell you that this inclusion is Cavity.

This inclusion type & location had a huge impact on lowering the diamond clarity grade to SI1, but it’s not the only thing that ended the diamond with SI1.

The inclusions found on the very first image to the left (crown of 1st diamond) are located at the worst location in a diamond (look again here using 360-degree, it’s easily visible), in many cases, they will be seen by naked-eye, and more importantly, they hugely effect diamond brilliance since light go through the crown.

So in a nutshell, inclusion location is very important to determine clarity grade and overall brilliance, always look for a diamond with less or no inclusions on the top, or on the girdle (and its upper/lower facets).

Diamonds Inclusions Summary

The inclusions in a gem can only be visible where the gem is loose. When it is in its setting, grading may be difficult because the prongs or the bezel may hide the inclusion. This could also be a good thing when gems with inclusions are purchased. The inclusions could be made to hide in plain sight with the chosen setting.

Whereas the freckles as stated above add beauty and are considered unique characteristics of an individual, they do not impact on the value attached to such person. Diamonds are however inanimate and are assessed based on the idea that they should, in fact, be perfect.

Find the One James Allen

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