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The Ultimate Guide to Diamond Inclusions

by Stephanie Dore

Flawless diamonds might be a celebrity’s best friend, but baby they’re not ours, and we’re going to run down why. Not only do high clarity diamonds demand exorbitant price tags, but frankly darling if you’re paying that price, you’re overpaying. Because the fact of the matter is that when it comes to clarity you’re paying for something you quite simply cannot see. And that’s true of the majority of diamond inclusions — you simply cannot see them! We know the marketing departments of many a retailer would like you to believe otherwise, but diamond inclusions aren’t nearly as scary (or visible) as they sound.

The Cold Hard Truth About Diamond Clarity

To the average human, it sometimes feels like there are only two types of diamond clarity: flawless and, well, flawed, right? But this couldn’t be further from the truth. Diamond clarity — when it comes to the actual grading system — is much more nuanced than that. In fact, there are a total of 11 different clarity grades! Diamond clarity is actually graded based on the absence of clarity characteristics. And these clarity characteristics are made up of two different groups: inclusions, which are internal to the diamond, and blemishes, which are on the surface of the diamond only. Very experienced diamond graders (armed with magnification equipment) evaluate the number, size, relief, nature, and position of these characteristics in each diamond, as well as whether, and how, these characteristics affect the overall appearance of the stone.

Clarity is the first C we recommend sacrificing. Most inclusions are difficult, if not impossible to see with the naked eye.
Diamonds are reflective by nature — that’s why they sparkle. But, that reflectivity also means a single inclusion can be reflected many times.

The Forever Fingerprint

When thinking about diamond clarity, please know that inclusions are not inherently a bad thing. They can even be a really good thing! It’s important to remember that natural, mined diamonds formed like a gazillion years ago, under intense heat and pressure, deep within the Earth. They’ve been through a lot! And their structure can show it. Inclusions are present in nearly every diamond, and are a bit like birthmarks or fingerprints — completely unique to each stone. They can even be used to help identify your diamond from all the rest. Plus, if you want to get super nerdy with us, some inclusions can actually look really cool!

The Good, The Bad, The Ugly

While we wish we could give you a blanket statement like “Don’t buy a diamond with this type of inclusion”, that would just be misleading and keep some really rad diamonds from ending up on your pretty little fingers. But what we can do is give you a little guidance about each inclusion type, what to watch out for, and how to buy a diamond you’re gonna love forever-ever. So let’s get into it!

If you see inclusion listed on a diamond certificate you can sometimes take a deep breath and relax.
Inclusions are small naturally occurring blemishes inside diamonds.

Bearded Girdle

Most diamonds sold today have intricately polished and faceted girdles (the outer circumference of your diamond between the crown and pavilion). But if you see “bearded girdle” listed on your diamond grading certificate, that means the diamond has a girdle that looks kind of like microscopic sandpaper, with teeny tiny feathers that extend from the outside girdle surface into the stone. This is a result of the cutting process, and like we said, is often polished away. If the girdle is also extremely thick, you might be able to see a slight opaque line around the diamond, but it’s usually not noticeable. 


Yes! Diamonds get bruises too! And it’s really just like it sounds — a bruise is usually the result of an impact that has happened post-polishing instead of during diamond growth. It will be a microscopic impact with teeny tiny feathers extending into the stone, often where two facets meet (which makes sense; since they’ll have a corner that might have gotten bumped). A bruise in and of itself shouldn’t ever be eye-visible.

A bruise in and of itself shouldn’t ever be eye-visible.
SI or lower grade cavity can occasionally be eye-visible.


A cavity can be any size or shape and is basically just an irregular opening or divot in the surface of a diamond. This usually happens when a feather or crystal breaks out during diamond cutting and polishing, leaving a craggy opening where it once was. Cavities are usually not a further breakage risk because, well, they’ve already had that risky part break out. But an SI or lower grade cavity can occasionally be eye-visible, or if located along the girdle, and you run your fingernail over it, you might feel a tiny nick in the edge, but this isn’t going to hurt the diamond or your eyeballs.


A chip is similar to a chip in anything else (except the potato kind), a shallow opening that is caused by damage to the diamond, usually after production, and often at its more delicate points like along the girdle edge or the culet. If you’re looking at purchasing a diamond shape with sharp points (like a princess cut, pear cut, or marquise) you’ll want to be sure to look out for chips pre-purchase, work with an expert diamond setter, and make sure that you set your stone in a protective setting that shields those points with metal to risk breakage from everyday wear. If you look at a diamond plot and it shows a large chip down a pavilion facet, there’s a chance that it will be reflected throughout the diamond, so keep an eye out!

A chip is usually on the surface of the diamond.
moissanite engagement ring
Many pinpoints hanging out together, like a microscopic, say, cloud…


A cloud inclusion is actually a cluster of smaller inclusions, usually pinpoints, where there’s just a lot of them together. Higher clarity grade stones with clouds are rarely something to worry about, but lower clarity clouds can cause transparency issues. Also, if the certificate notes that it is a grade-setting cloud, you’ll want to get eyes on the stone before you buy, as this typically notes something more noticeable or extensive throughout the diamond.


Just like the rough diamond crystal itself, a diamond can have other crystals inside of it! This can be nearly any other type of mineral, and any color for that matter. Clear or white crystals will be less noticeable, while dark crystals will be more noticeable. You won’t see the color of the crystal noted on the grading report, however, so this is something you might need help identifying. Crystals are also entirely contained within the diamond, not reaching the surface, and are not inherently risky to the diamond’s structure.

Crystals are entirely contained within the diamond and are not inherently risky to the diamond’s structure.
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Feathers are colorless and OK if they do not reach the girdle.


This is what we call any type of break in the diamond’s internal structure, because it often appears white and, well, feathery. Like, literally it looks like a teeny tiny feather! Feathers, like the rest of the inclusion types, can be any size. Whether or not a feather is more noticeable or less is usually dependent on its size, extension, and angle. Often from one angle you might not see it, but turn the stone to the side and you’ll see a tiny white flash, like a little crescent or similar. Small feathers completely contained within the diamond are not a structural risk, however larger feathers or feathers that extend to the surface of the stone can pose greater risk.

Grain Center

This isn’t like the Home Depot for gluten, y’all. Instead, a grain center is a tiny area of distortion in the diamond’s crystal formation. It can look like little threads or pinpoints where some refraction happens, and can appear light or dark. These are really not something that happens frequently or will ever be visible, so pretty low on the concern pole.

A grain center is pretty low on the concern pole and they occur occasionally.
Intended natural inclusions can be overlooked as it doesn’t compromise the integrity.

Indented Natural

While they might initially appear to be a cavity or chip, an indented natural is actually a little bit of the diamond’s original rough crystal surface that has been left behind after polishing. Indented naturals are always, well, indented below the polished surface, and often located along the girdle and not noticeable. They are not risky to the diamond’s integrity.

Internal Graining

Another inclusion type caused by the natural crystal growth, internal graining appears like lines or curves, usually in groups. It is often clear and reflective, however can be whitish or colored and affect transparency at 10x magnification. If internal grading is a grade-setting inclusion for a lower clarity diamond, you might want to steer clear. However for the most part, this isn’t the case.

Internal graining is a natural crystal growth.
Laser Drilling may affect the integrity of your diamond.

Laser Drilling

Laser drilling is not natural and usually done after the diamond is fashioned, to increase the clarity of a diamond. How so? Well, if there’s a visible crystal or feather, a diamond manufacturer might drill into that inclusion with a laser in order to fill it with bleach or chemicals that decrease that inclusion’s visibility. Obviously, it leaves behind a permanent drill hole. Not ideal. And if you see this listed on a certificate, we suggest steering clear, as this can often mean the presence of impermanent diamond treatments that can put the diamond at risk for daily wear.


A knot is simply a diamond crystal that reaches the surface. They can be clear or colored, and can be a risk for diamond integrity as most surface-reaching inclusions can. There is the risk that a knot can eventually fall out of the diamond, leaving behind a more noticeable cavity.

A knot is an inclusion that is generally visible.
Needle inclusions are only visible under 10x magnification.


Needles are tiny, elongated crystals — rod-shaped (like, you know, needles), and internal to the diamond. They are often very tiny and will not be eye-visible on their own, only visible at 10x.


Pinpoints are super tiny crystals that literally just look like tiny specks of dust at 10x magnification.

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To make a completely unique custom piece, you’ll want to customize your setting to fit your dream diamond!

Twinning Wisp

Caused by distortion during the diamond crystal’s growth, a twinning wisp often looks like wisps of cotton candy or, say, that fake Halloween spider web, through the stone. It can be a single tiny strand that doesn’t affect the stone at all, or in lower grade stones might be throughout and cause transparency concerns.

Skin Deep

Now that we’ve covered inclusions, let’s briefly talk about blemishes, which are constrained to the diamond’s surface, never internal. And the fact is — you’ll usually only see these noted on higher clarity diamonds because that’s when they really become part of setting the clarity grade (because lower clarity diamonds usually have more noticeable internal inclusions). Blemish types include minute nicks, pits and abrasions (usually along facet junctions), extra facets (not required by the cutting style and without regard for the diamond’s symmetry), naturals (similar to indented naturals, only not indented), leftover polishing lines, scratches, and surface graining (similar to internal graining). Blemishes are never a concern for eye-visibility.

Check out our diamond search to pick your match from over 10,000 diamonds.
If you simply must have a flawless diamond, then go for it! But in our humble opinion, clarity shouldn’t be at the top of your MVCs (most valuable Cs) list.

The Big Picture

While it’s helpful to know what types of diamond inclusions are out there (especially when reading a grading certificate), like we said up top, there’s a lot more that goes into clarity grading than simply inclusion type. It will be much more to your (and your wallet’s) advantage to think about purchasing an eye-clean diamond than a flawless one, as it’s rare for a diamond’s inclusions to be eye-visible to the untrained, unaided eye. That said, there are exceptions. If you’re purchasing a step-cut diamond (emerald or Asscher cut), rose cut, or portrait cut, these have larger more open facets so if you don’t want to see anything, you might need to stick to higher clarity grades. And the larger your stone is, the same is true. 

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