16 Types of Diamond Inclusions & Advice on Consideration

Interested in inclusions?

If you’ve already started your diamond-buying journey, you’ve probably noticed each stone has a clarity grade. A big part of a stone’s clarity grade is its inclusions, which are imperfections within a diamond that can range from barely visible to structurally damaging. Inclusions in diamonds are a major factor in both their durability and appeal, so let’s take a look at:

• Inclusion basics
• 16 types of inclusions
• Inclusions and clarity grading
• How to inspect inclusions
• Types of inclusions to avoid
• Inclusions in natural vs. lab diamonds
• Other considerations when buying a diamond

What are diamond inclusions?

An inclusion is a feature found within a diamond that interrupts its orderly carbon makeup. They can be irregularities within the stone’s structure or particles that became trapped during the formation process. 👉🏻Think of inclusions as birthmarks: they’re one-of-a-kind differences that set each diamond apart and are unique to that particular stone. They may be incredibly small or so large that they can be seen without a jeweler’s loupe, and they don’t all look the same.

Classification

There are a few ways in which inclusions form:

During the growing process

Most inclusions form during the formation process of the diamond itself. Diamonds form over billions of years under intense heat and pressure, where foreign substances can be introduced to their structure. Additionally, all that pressure and heat can cause slight irregularities, cracks, etc. that we refer to as inclusions once the diamond is cut.

During the cutting and polishing process

It’s possible for a gem cutter to create inclusions during the cutting and polishing process. This can be accidental or due to carelessness, but sometimes a gem cutter must make sacrifices to eliminate a possibly more intrusive inclusion by creating or exacerbating another one. This may be done for the sake of clarity grade or even to maintain as much rough as possible for weight purposes.

During daily wear

Diamonds are extremely strong, but they aren’t indestructible. As such, you can definitely damage a diamond through daily wear if you aren’t careful! Hitting your diamond the wrong way on a hard surface or exposing it to extreme heat or chemicals can cause fractures or make any current inclusions worse.

During diamond treatments

While treating a diamond for color, clarity, etc. a diamond may develop further inclusions. What’s more, some treatments—such as filling or laser treatments—are listed as inclusions due to the change in the diamond’s overall appearance.

16 types of diamond inclusions explained

There are several different types of inclusions that can be found within a diamond, and the GIA has classified 16 of these imperfections to help professionals determine a stone’s clarity. Here’s a brief diamond inclusions chart for reference:

Types of Inclusions

Inclusion Name	Description
Bearded Girdle	Hair-like feathers that occur during the cutting process and appear on the girdle stretching into the diamond’s surface
Bruise	Typically found near facet junctions, they’re small impact areas with tiny, root-like feathers that extend into the diamond
Cavity	A large, angular opening in the diamond from the breaking away of a surface-reaching feather or crystal during the polishing process
Chip	A shallow opening on the surface of the diamond caused by damage from wear and tear, they often appear at a girdle edge, on the culet, or near a facet junction
Cloud	A cluster of pinpoints or crystals tightly set together that cause a hazy appearance within the diamond
Crystal	A mineral inclusion within the diamond that can be colorless or colorful (red, blue, green, black)
Feather	A fracture within a diamond, which often has a white feathery appearance, surface-reaching feathers start inside the diamond and breach the stone’s outer edge
Grain Center	An area of crystal distortion that can appear white or dark in color with a pinpoint or thread-like pattern
Indented Natural	An area of the original rough diamond’s surface that dips below the polished stone’s surface
Internal Graining	White, reflective, or colored irregular crystal growth in the form of angles, curves, and lines that can take on a milky or hazy appearance.
Internal Laser Drilling	The result of laser drilling, they leave surface-reaching feathers or tunnels to access worse inclusions for clarity treatments
Knot	A transparent or white diamond crystal that reaches the surface of the stone
Laser DrIll Hole	A small, surface-reaching tunnel professionals create via laser beams
Needle	A needle-like crystal that is visible at 10x magnification and may appear white or transparent, they can also appear in clusters
Pinpoint	A very small black or white crystal inside a diamond that looks like a tiny dot at 10x magnification
Twinning Wisp	A collection of pinpoints, crystals, or clouds created during the diamond formation process as a result of restarted growth after a period of inactivity

Diamond inclusions and clarity grading

Clarity grading is a tricky thing, and gemologists painstakingly examine each diamond to ensure its grade is as accurate as possible. To grade a diamond’s clarity, experts must look at a few different facets of the stone’s inclusions:

Size: The actual size of each inclusion can impact a diamond’s clarity score. Stones with smaller, less visible inclusions receive a higher grade, while those with larger, more visible ones receive a lower grade.

Nature: The nature of an inclusion refers to its placement within the diamond and whether it poses a threat to the stone’s structural integrity, including whether the inclusion is internal or surface-reaching as well as classification such as crystal, feather, knot, cleavage, etc.

Number: The number of inclusions simply measures the amount, with higher-graded gems typically having fewer visible inclusions and lower-graded ones featuring larger or more visible clusters of imperfections.

Location: The location of inclusions also impacts the diamond’s grade, indicating how visible (or not) they may be. For instance, inclusions found under the table of the stone are more visible than those found near the edges, and inclusions near table or pavilion facets actually impact the dispersion of light for a less sparkly diamond. The best places for inclusions are near the girdle or crown facets, as these stones still tend to be “eye clean”.

Relief: The relief of an inclusion measures its color and visibility relative to the rest of the diamond. For example, a garnet crystal within a diamond carries color, making it stand out more and lowering the stone’s clarity grade. In contrast, a slight feather may appear clear and can be hard to notice, so it won’t impact the diamond’s clarity grade as severely.

How do graders inspect diamond inclusions?

Graders view diamonds through 10x magnification at multiple angles to grade each stone properly. They divide the diamond into sections per their facets and follow a planned inspection order, carefully examining each plane of the stone and taking note of any imperfections. Controlled lighting is also important for the best viewing environment, and so labs use darkfield and brightfield illumination to spot different kinds of inclusions.

Graders then give each diamond a clarity grade based on a precise and industry-wide scale. The scale ranges from Flawless (FL) near the top to Included (I1-3) at the bottom. Here’s a brief breakdown of each category to give you an idea of how graders divide up the diamonds into each grade:

Grade	Example	Description
FL	SKU*: 10041868	Flawless The best diamond clarity, they have no inclusions under 10x magnification and a perfect clarity score. When diamonds are FL or IF, their differentiating characteristic comes down to polish.
IF	SKU*: 9880092	Internally Flawless Similar to an FL grade, this diamond will have no internal inclusions visible to the naked eye. However, there may be minor blemishes on its surface.
VVS1	SKU*: 9082554	Very Very Slightly Included (1) Inclusions in this grade are so tiny that even experienced professionals have a hard time locating them under 10x magnification.
VVS2	SKU*: 6959995	Very Very Slightly Included (2) VVS2 diamonds have nearly undetectable inclusions just like VVS1 stones. However, if the inclusions are visible from the pavilion side, the gem will be a VVS1. If inclusions are detectable from face-up view, it will be a VVS2 as these inclusions are more noticeable.
VS1	SKU*: 9749294	Very Slightly Included (1) Affordable and eye clean, VS1s are one of the best deals on the diamond market! Inclusions are minute, and it would take 10x magnification and a trained eye to see them.
VS2	SKU*: 10171203	Very Slightly Included (2) Unlike VS1 diamonds, VS2 stones will have inclusions that are visible to any grader with 10x magnification. However, these inclusions are still tiny and leave the stone eye clean, so they are an affordable and quality gem for purchase.
SI1	SKU*: 10171242	Slightly Included (1) SI1 diamonds may be eye clean or not depending on the type of inclusions they carry. However, whether they grade as eye clean or not, the inclusions will always be visible under 10x magnification.
SI2	SKU*: 9749466	Slightly Included (2) Inclusions in SI2 gems are larger and more visible than those in SI1 diamonds, and they can affect color as well. Eye clean SI2s do exist, but you’ll have to shop around to find them.
I1	SKU*: 9883508	Included (1) I1 stones MAY be eye clean on rare occasions, but often they contain major flaws. These inclusions tend to affect sparkle and transparency, causing the diamond to lose its characteristic luster.
I2-I3	Most jewelers do not sell diamonds with a clarity grade in this range.	Included (2 & 3) Included 2 & 3 diamonds are not recommended for purchase, as they are never eye clean.

Note: *Diamonds in the chart are from James Allen; these diamonds have the same carat, cut and color gradings: 1 carat, Excellent (Ideal) and G.

Advice on inspecting inclusions in a diamond

Clarity is a nuanced characteristic of a diamond’s sparkle, so how can you be sure you’ve made the right call when choosing your own stone? Here are three methods we suggest for finding a good quality stone at a decent price:

Review the diamond plot

Your first line of defense when it comes to clarity is the diamond plot. The diamond plot is a map of diamond inclusions or blemishes, and it often includes two images: a face-up diamond and a bottom-up diamond. Graders add special markings and colors to denote the presence of inclusions and blemishes and map out exactly where they are within the stone—red identifies inclusions, while green indicates blemishes.

The diamond plot gives you a better idea of where you should search for inclusions in a diamond when examining it, giving you a little head start so you can identify any that impact sparkle, color, etc. ⚠️However, a diamond plot should never be used alone, as the plot cannot tell you how greatly a marked inclusion impacts the diamond’s overall appearance. In fact, some inclusions aren’t listed in the plot, but rather they appear in the “Comments” section of the diamond grading report. So it’s important to combine both the diamond plot and the comments section with an additional method below to make sure you’ve thoroughly examined your stone.

Use a diamond loupe and consult a jeweler

In addition to the diamond plot, it’s a great idea to consult with a trusted jeweler. Jewelers often have decades of experience examining diamonds, so they can help you find inclusions within your stone and explain any impacts they may have on sparkle and beauty. You should also take the time to look at your diamond through a jeweler’s loupe, which you can find online or borrow from your jeweler. Inspecting your diamond under 10x magnification with a trusted expert is a great way to pinpoint any troublesome inclusions and better comprehend how even unproblematic inclusions will appear as your diamond sparkles.

Take advantage of 360° images and/or videos

Many online retailers are moving to innovative 360° images and videos to help shoppers who can’t view diamonds in person at a showroom. These high-resolution images and videos give you an up close and personal look at the fire, brilliance, and scintillation of a diamond, offering you a chance to watch the stone sparkle and see any inclusions that aren’t invisible to the naked eye. That way, you can feel better about making an online purchase rather than buying a diamond “sight unseen”!

Types of inclusions to avoid for the best value

Overall, you’ll run into some inclusions more than others during your search, as some are rather common while others are rare to come across. As a general rule of thumb, it’s best to avoid inclusions with darker coloring (whether they’re translucent or opaque), located close to the diamond’s table where they’re most visible, near weak areas within the stone such as corners, and avoiding certain inclusions altogether if you can.🙌🏻 These inclusions can greatly impact a diamond’s lightplay—which is key to ideal sparkle—and sometimes pose durability issues that make it easier for dirt and oil to accumulate on or within your stone. We recommended staying away from:

Surface-reaching feathers

An internal crack in a diamond can be tricky enough, but surface-reaching feathers pose additional problems for a stone’s durability. Feathers come in all shapes and sizes and can be black or white, but any feathers that reach the surface of the diamond pose a greater risk of creating weak points, especially near the girdle of the stone. Large feathers can also decrease brilliance and impact light entering the stone, and when they reach the surface they’re even more of a visual nuisance. Small or transparent feathers within a diamond are a part of their natural formation process, but steer clear of any that breach the surface of the stone.

Chips

Small openings on the surface of a diamond can cause serious problems in the long run, typically forming near the girdle, culet, or intersection points of facets. As such, they create weak points in the diamond and make it susceptible to future breakage during daily wear in addition to impacting the stone’s value and overall appearance. Chips are typically manmade and a product of a hard hit or dropping the diamond. They’re also fixable if you’re willing to sacrifice a little carat weight to have the stone recut, but we suggest just purchasing a diamond without a chip to save yourself some time and money.

Dark crystals

Even if the crystal within your diamond is another precious gem like an peridot, it’s still not going to increase its value. In fact, it’s quite the opposite: crystal inclusions can come in dark colors like green, blue, and red and can impact light performance. Some crystals are clear, and you can typically purchase diamonds with these inclusions without much worry since they won’t severely impact lightplay. But, if there’s heavy color, avoid them! Enough color from a dark crystal can stop light from properly entering the stone, and you sacrifice fire and brilliance as a result. If you decide on buying a diamond with dark crystals, try to find one where the colored pieces will be covered by the setting for the best sparkle.

Heavy clouds

One or two pinpoints isn’t a problem, but multiple pinpoints close together form a cloud. If clouds are dense or large, they can impact the overall appearance of your diamond. Heavy clouds create hazy areas within a stone, impacting light performance and hindering fire, brilliance, and scintillation. As such, avoid any stones with heavy clouds, but diffuse or tiny clouds aren’t typically an issue.

Knots and cavities

Both knots and cavities impact the durability and appearance of a diamond, placing them on the “avoid if possible” list. Knots are often visible to the naked eye and can’t easily be masked, even though they’re typically white or transparent. That’s because they’re on the surface of the diamond, and being so close to the surface means knots can produce weak points that impact a diamond’s overall durability.

Similarly, cavities are holes that are visible to the naked eye, and they greatly impact the durability of the stone and leave it open to more damage in the future. In addition to breakage, these openings can fill with debris and appear black or discolored, affecting the appearance of the diamond. Cavities are similar to chips in that they can be fixed, but you’ll have to shave off some carat weight to make it happen.

Laser drilled holes

When gem cutters remove an inclusion from a stone, they leave behind holes where they were working. Laser drilled holes themselves aren’t always a problem, and a diamond expert will try to minimize the effects of the work by making the tiniest tunnel possible and avoiding excessive carat loss. But, by virtue of having these holes, the diamond is now clarity enhanced, which decreases its value. So, if you have a clarity enhanced diamond and an identical natural one with inclusions, the natural diamond is actually more valuable. Overall, if this doesn’t matter to you, then it’s just a matter of finding a clarity enhanced diamond for a good price.

Inclusions in natural vs. Lab-grown diamonds

If you’re looking at lab-grown diamonds as a potential alternative to natural ones, you’ll be happy to know that lab diamonds have very minor (if any) inclusions in their makeup. That’s not to say that a diamond without inclusions can’t be natural, and both types of diamonds have the potential to be heavily included or flawless.

Lab diamond inclusions are often a result of their growing process. For instance, lab diamonds created via the High Pressure High Temperature (HPHT) process may contain tiny metal inclusions—such as iron, cobalt, and nickel—as a result of small pieces of flux becoming trapped within the forming gemstone. They may look white or gray with a metallic appearance in reflected light, and they can appear individually or collected in small groups. 😆Fun fact: depending on the location and size of iron inclusions, you could potentially pick up an HPHT diamond with a magnet! However, these inclusions are typically rather small and don’t impact overall appeal.

For diamonds created via Chemical Vapor Deposition (CVD), metallic inclusions aren’t an issue. Instead, CVD diamonds contain mineral inclusions like graphite due to their complex growing process. These graphite inclusions appear as dark spots or crystals within the diamond, lacking the metallic shine of those found in HPHT diamonds.

Other aspects to consider when evaluating a diamond

In addition to finding an eye-clean diamond, there are a few more considerations to keep in mind on your diamond-buying journey. We recommend paying close attention to:

Diamond shape

Did you know even the shape of your diamond can impact how visible inclusions appear in your diamond?🤔 Shapes with larger tables tend to show off inclusions, with emerald, Asscher, and baguette cuts requiring higher clarity grades to be considered “eye clean”. We recommend a VS2 grade or higher for any of these elongated silhouettes! If you’re looking for a shape that will mask inclusions, try round, heart, oval, marquise, princess, pear, and radiant silhouettes instead. These shapes are masters at hiding inclusions, and you can find good, eye-clean stones even with an SI clarity grade.

👉🏻Diamond shapes with points also introduce potential weak points that should be protected, especially if you choose a stone with a lower clarity grade. Inclusions close to these weak points can cause structural damage when hit with enough force, so be sure to choose the right setting for your diamond shape with proper prongs or opt for something more protective like a halo or bezel.

Cut style

Diamond cut can also impact the visibility of inclusions, and brilliant cuts mask imperfections better than step cuts. Step cuts, such as emerald, Asscher, and baguette, have long, uninterrupted facets that act as mirrors, giving you the opportunity to see everything all the way to even the bottom of the stone. As such, those pesky inclusions become pretty visible if they’re not tucked away!

In contrast, brilliant cuts offer intense sparkle that easily masks inclusions. The highly faceted nature of brilliant cut diamonds means that light enters and exits the stone at various angles, "hiding" inclusions and distracting the eye with fire, brilliance, and scintillation. That being said, a large enough inclusion or one below the diamond’s table can still be seen in the right lighting or with a jeweler’s loupe, it just may be much harder to locate compared to a step cut stone.

Diamond color

The relationship between diamond color and clarity is a balancing act! Diamonds in the G to I color range have a very slightly warmer tone that helps them mask inclusions, so you can more easily find stones in the SI clarity range that look eye clean. On the other hand, if you want a bright white diamond in the D to F color range, you’ll need to shell out a bit more cash to keep that eye-clean appeal! Because whiter diamonds are clear and more readily display inclusions (remember: inclusions can have slight color), you might want to stick to VS2 or above for these finicky stones.

Summing up

As you can see, there’s much to learn when it comes to the science of diamond inclusions! However, with this helpful guide, you should be able to spot critical inclusions like a pro and better understand how to identify an eye clean diamond, and you can always consult a diamond professional if you’re still unsure. James Allen is known for their 24/7 access to non-commissioned diamond professionals, so we recommend giving their website a try if you haven’t already! For more information on how diamonds are graded, check out our guide to the 4Cs of diamonds.