Feather inclusions in a diamond are among the most common inclusions to be found.
In some cases feathers can neither be seen by the naked eye nor do they pose a risk to the durability of the diamond. In other cases however, a feather can not only be a serious appearance concern but it could also potentially pose a durability risk.
That is reason enough to have a close look at diamond feather inclusions.
Let’s do it in an orderly manner.
What is a Feather Inclusion in a Diamond?
The term “feather” in a diamond grading report refers to a small internal break or fracture within the diamond. Despite the name, it has nothing to do with actual feathers. Some first-time buyers even wonder if real feathers can be trapped inside a diamond, but that would be extremely rare.
Feathers get their name because they often have a light, wispy appearance that can resemble the texture of a feather. They can vary in size, shape, and location, and may be completely internal or reach the surface of the diamond.
On a grading report, feather inclusions are typically marked in red on the clarity plot. All major grading laboratories, including GIA, IGI, and AGS, use the same general symbol to indicate a feather. In 2022, AGS was officially merged into GIA, and their grading standards and symbols were unified under the GIA system.
The impact of a feather depends on its size, location, and whether it breaks the surface. Some are harmless and invisible without magnification, while others may affect appearance or even pose a durability concern.
Are Feather Inclusions Common?
Yes, feather inclusions are one of the most common types of clarity features found in natural diamonds. In fact, they appear across nearly all clarity grades, from flawless-looking VS diamonds down to heavily included I clarity stones.
Feathers form naturally during a diamond’s long journey from deep within the earth. They can occur during the diamond’s growth or be caused by internal stress released during cutting and polishing. Because of how frequently they occur, most diamonds on the market today contain at least one small feather inclusion.
If you are curious how feathers compare to other common inclusion types in terms of visibility and durability, take a quick look at the table below:
| Diamond Inclusion Types – Quick Reference (Most Common) | ||||
| Inclusion Type | Occurrence | Description | Visibility Risk | Durability Concern |
|---|---|---|---|---|
| Crystal | Very Common | Small mineral or diamond crystals inside the gem | Moderate to High | Low |
| Pinpoint | Very Common | Tiny white, gray, or black dot-like inclusions | Low | Low |
| Feather | Common | Minute internal fracture, may appear transparent or white | Low to Moderate | Moderate to High |
| Cloud | Common | Cluster of pinpoints that look hazy under magnification | Moderate | Moderate |
| Needle | Moderately Common | Long, thin, white or translucent crystal | Low | Low |
| Twinning Wisp | Moderately Common | Twisted growth pattern made of clouds, feathers, and pinpoints | Moderate | Moderate |
As you can see from the table, the feather inclusion is the only common clarity feature with a moderate to high durability concern. That alone is reason enough to give it special attention. This guide was created to help you understand when a feather is harmless and when it should be avoided.
The good news is that not all feathers are created equal. Many are tiny, hidden in areas that are impossible to detect without magnification. Others, however, are more prominent and may affect the diamond’s beauty or strength. The key is knowing how to spot the difference between harmless and problematic feathers.
In the next sections, you’ll learn how to identify feather inclusions on grading reports, how visible they really are, and when they may affect the diamond’s durability.
What Do Feather Inclusions Look Like on a Grading Report?
Feather inclusions are usually shown as fine, curved red lines on a diamond grading plot. These diagrams are a map of the diamond’s internal and external characteristics and appear in most grading reports issued by labs such as GIA and IGI.
In a standard round diamond plot, the left diagram shows the diamond from the top view (crown), and the right diagram shows it from the bottom view (pavilion). Feather inclusions are marked using a specific red squiggle-like symbol. If the feather reaches the surface, it will still appear as a feather symbol, but the lab may also note it under comments or show a related surface-reaching inclusion type, such as a cavity.
In the example above, you can see a feather inclusion located just beneath the table area, extending toward the girdle. It is not at the very edge of the diamond but close enough to potentially raise a durability concern depending on its depth and whether it reaches the surface. The plot also includes other inclusion types, such as a needle, pinpoints, and an indented natural. Together, these markings form a complete grading diagram that gemologists use to assess the clarity and structural integrity of the diamond.
Understanding the location and orientation of a feather in these diagrams can help you judge how visible or risky it might be in real life.
Do Feather Inclusions Affect Diamond Durability?
So what about durability? Can a feather inclusion actually weaken a diamond?
The short answer is yes, but it depends on the feather’s location, size, and whether it reaches the surface. Feather inclusions are most often flagged as a potential durability concern when they are situated near the girdle or when they extend to the surface of the stone. However, feathers may also pose a risk if they are particularly long and positioned along facet edges, or if they appear in combination with other inclusions, such as crystals or cavities. These additional factors can increase internal stress and raise the likelihood of chipping under impact.
To give you a clearer picture, the table below breaks down how different types of feather inclusions affect durability based on both their structure and the clarity grade of the diamond:
| Durability Risk Levels of Feather Inclusions | ||
| Feather Type | Common in Clarity Grades | Durability Risk |
|---|---|---|
| Feather reaching the surface | SI1, SI2, I1 | High |
| Feather crossing through the girdle | SI2, I1 | High |
| Feather combined with crystal or cavity | SI2, I1 | Moderate to High |
| Long feather near girdle but internal | SI1, SI2 | Moderate |
| Short feather near center or pavilion | VS2, SI1 | Low to Moderate |
| Small internal feather, fully enclosed | VS2 and higher | Low |
As shown in the table above, there are only two types of feather inclusions that typically carry a high durability risk. These are feathers that reach the surface and feathers that cross through the girdle.
A feather that reaches the surface creates an opening in the diamond’s structure, which can make it more vulnerable if it receives a strong impact. A feather that crosses through the girdle presents a different kind of concern. This means the inclusion begins in the upper half of the diamond and continues into the lower half, cutting across the girdle. The girdle is the thin edge that separates the top and bottom views in a grading plot. When a feather passes through this area, it can form a natural fault line within the diamond. This internal weakness may increase the chance of chipping or splitting, especially if the stone is hit at a vulnerable point.
The clarity plot below shows exactly this type of inclusion. The same feather appears in both the upper and lower diagrams, aligned in the same position. This is a clear sign that it travels across the girdle from one side of the diamond to the other.
This grading plot shows the diamond from two different angles. The top image represents the crown view, which shows the diamond as seen from above. The bottom image shows the pavilion view, which presents the diamond flipped upside down and viewed from below.
Both diagrams follow a consistent orientation. Position one is placed at the top of the upper diagram and at the bottom of the lower diagram. This layout reflects how the diamond is turned during inspection. When the diamond is flipped vertically, what was once the top becomes the bottom, allowing gemologists to examine both halves of the stone in alignment with the girdle.
In this example, the same feather inclusion appears in both views at the same relative position. This tells us that the feather stretches through the entire diamond, from the upper half to the lower half, directly across the girdle. When an inclusion passes through the girdle like this, it forms a natural plane of weakness inside the stone.
This is a textbook example of a feather that could affect durability. Even if it is not visible without magnification, its location and structure can increase the risk of chipping or internal splitting, especially if the diamond receives a sharp blow at that point. These are the types of inclusions that gemologists are trained to identify, and that cautious buyers should watch out for.
Pro tip:
If you are ever unsure about a feather inclusion, ask the vendor whether it reaches the surface or crosses through the girdle. James Allen, Blue Nile, and Whiteflash are our most recommended vendors and all offer live chat support with diamond experts who can help you review clarity details before you buy.
For a hands-on experience, try James Allen’s Real Time Diamond Inspection. In most cases, you will be connected with a gemologist in under ten seconds. You can spin the diamond, zoom in, draw on the screen, and leave notes while chatting directly with an expert in real time.
I have already discussed feather inclusions in VS2 diamonds, but readers often ask me about inclusions like the one below. In VS2 clarity diamonds, these types of feathers are typically very small and not considered a serious durability concern. Their size and location usually fall well within safe limits.
Take a look at the VS2 diamond below from James Allen. You’ll notice several tiny feather inclusions positioned along the girdle, stretching between the upper and lower halves of the diamond. Although they span across the stone, these feathers are very small and shallow. In VS2 clarity diamonds, inclusions like these are not considered a durability concern, their size and location keep them well within safe structural limits.
Although the feathers in this VS2 diamond appear to stretch from the upper half to the lower half, they are extremely small and do not reach the surface. For a feather like this to pose a real durability concern, the diamond would typically need to be graded SI2 or even I1, where inclusions are larger and more likely to create structural weaknesses.
What Does a Durability Concern Really Mean?
When we talk about a durability concern in a diamond, we are not saying the diamond is going to break in half the moment it is worn. Diamonds are still one of the hardest materials on earth. However, a feather inclusion located in the wrong place especially one that reaches the surface or crosses the girdle can create a weak point in the crystal structure.
If the diamond is struck at exactly the wrong angle, especially along the girdle or facet edge where pressure concentrates, it can chip, fracture, or in extreme cases, cleave along the feather plane. It does not explode or shatter like glass, but it can break off in a sharp, sudden way. This is most likely to happen from an accidental impact like hitting the ring on a hard surface or dropping it onto tile or stone.
The image below shows two real diamonds that have suffered serious chipping. This kind of damage is often the result of a feather inclusion that reached the surface or crossed the girdle, forming a natural fault line. When struck at just the wrong angle (often during a fall or sharp impact) the diamond can break in a sudden, jagged way. It is important to remember that this is extremely rare, but these examples show what can happen when high-risk feathers go unnoticed.
That said, this kind of damage is very rare. It happens most often in I1 diamonds or lower, where feathers are more likely to be large, surface-reaching, or paired with other inclusions. In diamonds with higher clarity grades, like VS2 or better, feather inclusions are usually too small to create any real structural risk.
As long as you choose a well-cut diamond and avoid stones with obvious red flags, the chance of experiencing any kind of structural failure is extremely low even with daily wear.
Are Feather Inclusions Visible to the Naked Eye?
In my post about diamond clarity, I explained the main rule for getting the best value for your money. Choose a clarity grade between VS2 and SI2.
A VS2 clarity diamond graded by GIA will almost always be eye clean. There are only very rare cases where a VS2 diamond shows visible inclusions. This is why many buyers choose to go slightly lower in clarity, aiming for an eye clean diamond in the SI1 or SI2 range, which can offer even greater value. I would recommend avoiding I1 diamonds, as I have personally never seen one that is eye clean.
Fortunately, feather inclusions are among the least noticeable inclusion types. Because of their light color and slim, wispy shape, they tend to blend into the facets of a well-cut diamond and are often invisible without magnification.
Take a look at the H color SI2 diamond below. The feather inclusion shown here is more prominent than in the VS2 example above. On the clarity plot, the feather appears quite large, stretching across a noticeable portion of the diamond’s profile. Under 40x magnification, it is clearly visible and distinct.
That said, this diamond could still appear eye-clean to many people in normal lighting conditions. The feather blends somewhat into the surrounding facets, and its location may allow it to go unnoticed during casual wear. As with most SI2 diamonds, evaluating the stone in person or through high-resolution video is key. What looks concerning under magnification may be perfectly acceptable on the hand.
To sum it up, feathers rarely affect the overall appearance of a diamond. It is more often inclusions like dark crystals, twinning wisps, or large clouds that cause visible distractions.
Of course, most buyers do not worry about identifying specific inclusion types. To the untrained eye, an inclusion is simply an inclusion. But because of their thin and whitish form, feather inclusions are generally not a major factor in how a diamond looks.
By the way, if you want to see how feather inclusions look in real diamonds, the best place to do that is on James Allen or Blue Nile. They offer high-definition 360-degree videos for every diamond in their inventory, with zoom levels of up to 40 times. You can rotate the diamond freely and inspect every angle with exceptional clarity.
In fact, James Allen’s display technology often lets you examine a diamond more closely than you could in most physical jewelry stores. It is one of the best tools available if you want to judge feather visibility with your own eyes before making a decision.
Our Key Takeaway
Feather inclusions are one of the most common clarity features in diamonds, and in most cases, they are harmless and invisible to the naked eye. Their slim and whitish appearance means they rarely affect a diamond’s beauty. However, in certain situations, a feather inclusion can pose a real durability risk.
Here is when you should be cautious and possibly walk away:
- If the feather reaches the surface, especially near the girdle or facet edge
- If the feather crosses through the girdle, running from the top to the bottom of the diamond
- If the feather is long and located close to an exposed edge
- If the feather is combined with a crystal, cavity, or other inclusion in the same area
- If the diamond is graded SI2 or I1, where feathers are more likely to be larger and more disruptive
By contrast, small internal feathers in VS2 clarity or higher are almost never a problem, and many SI1 diamonds also offer excellent value without any real risk.
If you want to be sure, review the grading plot, examine the diamond using 360-degree video, and ask whether the feather reaches the surface or crosses the girdle. Vendors like James Allen, Blue Nile, and Whiteflash all provide expert assistance and inspection tools to help you feel confident in your decision.
When in doubt, remember this:
If the feather is big, deep, or near the edge leave it. If it’s small and tucked away, it’s usually safe to keep.
Frequently Asked Questions About Feather Inclusions:
Can a feather inclusion make a diamond break?
In rare cases, yes. If the feather is in a vulnerable location and the diamond receives a sharp impact, it can cause chipping or cleavage. This is more likely in SI2 or I1 clarity diamonds.