Diamond Inclusions: The Complete Guide

by DMNDS | Last Updated: March 13, 2020

What Are Inclusions In Diamonds?

Simply put, diamond inclusions are imperfections in the stone.

Inclusions are occur when diamonds undergo intense pressure during their formation. The higher the number of inclusions or the larger the inclusion is, the lower the clarity grade of the diamond will be.

“Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.'”

Gemology Institute of America

Do All Diamonds Have Inclusions?

The extremely rare flawless diamond has no inclusions, even when studied under intense magnification.

With that said, nearly every diamond has a certain degree of inclusions. These are personal identifiers for a stone’s integrity (i.e. stone fingerprint).

Below is an in-depth overview of the most common types of diamond inclusions. Read on to learn which inclusions you should absolutely avoid when making a purchase.

Diamond Inclusions to Avoid

Not all inclusions are created equal. In fact, there are two specific types that will greatly depreciate the value of the diamond. These are the diamond inclusions to avoid:


diamond inclusions

A chip is a missing piece in the diamond. These are commonly seen at the edge of the stone. It is rare for retailers to sell a chipped diamond. If they do, it should be a largely discounted price. Chips usually occur during natural wear and tear. If you chip your diamond, you can have it re-cut. Keep in mind; this will result in a smaller and less valuable stone.

Dark Carbon Spots

diamond inclusions
Photo: Steve Jurveston

As always, the flawless diamond is the most coveted. Black carbon spots are occur during the diamond formation. They are carbon pieces that haven’t fully crystallized yet. Ultimately, these spots block light from beaming through and hinder a diamond’s classically sought after radiant shine. One of the first flaws easily visible, even to the naked eye are these dark spots. Avoid them at all costs.

These are the diamond inclusions to avoid as they are hands down more damaging to the integrity of the stone than their peers outlined below. With those two out of the way, let’s move on to other types of common diamond inclusions.

Most Common Types Of Diamond Inclusions

Diamond inclusions can range from microscopic to large enough to see with the naked eye. They span the gamut of shapes, colors and sizes. Here is a breakdown of the most common types of diamond inclusions and how they factor in to a diamond’s clarity.


diamond inclusions

Pinpoints are the most common type of diamond inclusion. The pinpoint is a very minute crystal inside the diamond that usually resembles a small white light. In most cases, they are so difficult to see that even under the 10x magnification used in a diamond grading process, they can be hard to identify. With that known, the presence of a single pinpoint will not vastly depreciate a diamond’s clarity. However, if the pinpoint is darker in color (gray or black) this will cause a substantial affect on the clarity of the diamond.


diamond inclusions

Clouds are a type of inclusion, stemming from the existence of multiple pinpoints. If they are close together, they begin to form a haze, next of kin to a cloud. Much like a pinpoint flaw, a cloud will isn’t seen without special equipment but can affect the clarity of a diamond. If the pinpoints are plenty, you can expect to see them in the form of red dots on a grading report, fully visualized on the diamond’s visual rating.


A feather inclusion looks like a variety of cracks, that sembles the vision of a feather. If a feather inclusion is short, then a stone clarity will not be affected. However, if a feather inclusion is long and extends with stress points, which increase the risk of snaps or larger cracks and this will definitely have an effect on the rating. As the fissures increase, the durability decreases. The unfortunate result could mean a Meaning over time a stone is susceptible to complete destruction.

“If the stone is hit precisely on a feather or other surface-reaching inclusion, it might chip. Likewise, very deep feathers that extend from the crown to the pavilion, or that penetrate about one-third of the way or more into the diamond, could pose durability concerns.”

Gemology Institute of America

Included Crystals or Minerals

diamond inclusions

An included crystal or mineral within a diamond is classified by its size and structure. If these do not crystallize prior to the diamond’s full formation, they become the dark spots referenced above. As most inclusions are invisible without special equipment, these inclusions can get large enough to be seen by the naked eye. These definitely affect the stone’s clarity, even if they cannot be seen.


diamond inclusions

Diamonds can get cavities too. A cavity is a small but noticeable space within the structure of a diamond that can be filled with oil/dirt. This is a big problem, as inner implications of external influence depreciate the value and durability of a stone. These cavities can be present all over a diamond, and they are not bound to a certain size or location.


A bearding inclusion is a big mark, which can often be found at the diamond’s girdle after a diamond has been recut or bruted. They often look like a strand of hair and do not present a structural problem. However, bearding does reduce the brightness and luminescence of a stone. A bearded stone needs to be recut and polished regularly to retain luster.


A graining inclusion is not a natural line flaw. They occur during improper crystallization or diamond twinning. These cannot be removed with polish or cutting, and can even make a graining more visible or harder to cut in the future. The most susceptible stones to graining are Macles, as they have a triangular shape. The highest grade a grained diamond can receive is internally flawless. In most cases, this external inclusion is not visible but can be quickly determined by an expert.


A knot inclusion comes all the way to the surface from within. They can be recognized without any special equipment under certain light conditions if they are large enough. Knot formations can also raise the facet of a diamond causing variances in the surface to the natural touch. The presence of a knot can also impact the durability of a stone.


A needle inclusion is not visible to the naked eye unless it is of luminescent color and has a significant presence. Some needle inclusions can be positive as they add to the diamond’s aesthetic and make it more visually pleasing. Diamond crystals in a diamond can also be present in the form of long and thin needles. These may not be visible to the naked eye unless the needle inclusion is of a noticeable color or has a noticeable presence. Some needle inclusions are also give diamonds a special look.


Prior to purchasing a piece of diamond jewelry, ensure that you obtain and have full understanding of the clarity rating. If possible, avoid stones with chips and dark spots.

Lastly, remember that although nearly all diamonds have some form of inclusion, they are rarely seen by the naked eye. With that said, they do have a strong impact on the worth of the diamond.