Diamond clarity characteristics is how we refer to the inclusions within diamonds. You might consider diamond inclusions to be good or bad depending on inclusion type, location, or the extent that they cover a percentage of the diamond.
Some people decide whether diamond inclusions are desirable or not based on the degree of visibility with or without magnification. For example, if you're looking for a diamond which is eye clean then you might consider a diamond with inclusions that are readily visible without magnification to be bad.
While another person might be perfectly comfortable being able to see the inclusions within their diamond readily and immediately without magnification.
With the aforementioned concept in mind, I would like to suggest that there is no such thing as a bad diamond inclusion. Rather there are just different types of diamond clarity characteristics and some are more desirable than others depending on the size, location, and extent of the inclusions within the diamond.
At the same time, there are certain types of diamond inclusions that we automatically reject for at Nice Ice. This is because these types of diamond inclusions present a potential durability risk. However, our policy to reject diamonds that contain certain types of inclusions does not make those very characteristics good or bad. It is merely a reflection of our personal preferences and our desire to help you avoid buying a diamond which contains inclusions that may pose a durability risk.
Keeping in mind that every inclusion is individual and unique it stands to reason that every diamond must be evaluated on its own merits. Therefore it is not reasonable for us to make a blanket statement saying which types of diamond inclusions are the best. However, it also stands to reason that some types of diamond conclusions are more desirable than others.
With that in mind, it's fair to say that diamond crystals in all shapes and sizes tend to be our favorite type of inclusion. This is because diamond crystals are simply smaller diamonds that were absorbed by the larger diamond crystal as it formed.
At the same time, the size, location, and appearance of diamond crystal inclusions will affect their desirability. For example, a small collection of pinpoint size diamond crystals (also known as a cloud) is likely to be of no consequence. Whereas a large diamond crystal that is black in color located directly under the table facet of a diamond is not likely to be a desirable characteristic.
Of course, it goes without saying that every diamond is unique and must be evaluated on its own merit. While the diamond clarity inclusions listed above are generally acceptable it is still possible for us to reject a diamond based on the extent of the inclusions.
Which is why we recommend taking advantage of our Free Diamond Concierge Service by asking us to review the details for any diamond you may be considering.
The clarity characteristics or "Key to Symbols" section on a diamond grading report indicate the type of inclusions contained within the diamond. This section is highlighted in green on the diamond grading report pictured to the left for this Brian Gavin Signature Hearts and Arrows diamond.
The term "clarity characteristic" refers to the inclusions within a diamond. The inclusions form the basis for the clarity grade assigned to a diamond by a gemological laboratory.
In this instance, the SI-1 clarity grade of this diamond is based on the presence of crystals and clouds which are diamond crystals of different shapes.
This section of our website is intended to be used for educational purposes only. Keep in mind that the inclusions within each diamond are as unique as a snowflake and that no two diamonds will contain the exact same inclusions or formations.
The examples contained herein are "examples" and not absolute indications of what the inclusions will look like within other diamonds. Rather, each inclusion type represented here is an example of that type of inclusion in its basic form. The inclusions within any other diamonds that you are considering will look different. Every diamond must be evaluated on its own merit.
The key to determining the type of clarity characteristics (inclusions) within diamond is contained within the plotting diagram and key to symbols.
The top half of the diamond is represented by the diagram pictured on the left and the lower half of the diamond is represented by the diagram pictured on the left.
Imagine folding the right half that is the bottom under the top half on the left by creating a fold line in the middle of the two halves. The nine o'clock region of the bottom half aligns with the three o'clock region of the upper half.
Inclusions will be indicated on the section of the plotting diagram where the inclusion is located. However, it's important to realize that the inclusions might not be visible from that vantage point.
Thus, an inclusion may be indicated in the lower half of the diamond as is the feather indicated by the green arrow in the lower plotting diagram on the right. While the actual inclusion may be visible in the face-up position. This is because the facets of a diamond are like tiny windows that make it possible to see inclusions from many different vantage points.
The industry standard for diamond clarity grading is 10x magnification. However, the majority of diamond clarity photographs and video used to show the inclusions within diamonds online is closer to 35x which makes a U.S. Dime look like this.
A standard U.S. Dime measures approximately 17.9 millimeters. While the average one carat round brilliant cut diamond has an outside diameter closer to 6.5 mm.
To put this in perspective, the pink eraser on a standard #2 yellow pencil also has an outside diameter of about 6.5 mm. Remember this point of reference when shopping for diamonds online because the inclusions within diamonds can look pretty scary at 35x magnification.
It is quite common to find the comment "additional clouds not shown" and/or "additional pinpoints not shown" within the comments section of diamond grading reports.
This is because gemological laboratories like the AGS and GIA only indicate the primary inclusions in the key to symbols section located under the plotting diagram. The inclusions indicated in that section of the diamond grading report are considered substantial enough to be used as identifying characteristics.
Whereas the comment "additional clouds and pinpoints not shown" indicates that a trained grader saw the inclusions during their evaluation of the diamond. However, those inclusions are not substantial enough to be used for identification purposes.
Which means that you shouldn't worry about comments like "additional clouds or pinpoints not shown" when you see it under the comments section of a diamond grading report. Because the odds are that you're going to burn your eyes out trying to find those inclusions using a 10x power diamond grading loupe.
Those inclusions are "literally of no consequence" which is why they don't appear on the plotting diagram.
With regard to “clarity characteristics” a chip is a mark or flaw located on the surface of the diamond made by the breaking off or gouging out of a small piece. This is often confused with the term “diamond chip” which refers to an extremely small diamond. Just for fun, both types of diamond chips are nouns.
A chip in the surface of a diamond most often occurs as the result of a slight impact. For example, the chip on the bottom of this princess cut diamond was most likely caused by a downward impact. The diamond was pushed down into the setting and the pressure chipped the bottom point known as the culet.
People frequently request to have their diamond set as low as possible in the prongs. However, chips like this are the reason we like to leave a little space between the culet and the base of the head.
The diamond tends to press down a little when the prongs are being crimped into place. The extra space might act as a pad that allows for an unexpected downward impact. Thus the chance of accidentally chipping the diamond during the setting process is reduced.
Most chips like this are minor and can be removed from the surface of the diamond by re-cutting or polishing the gem with a minimal loss of weight.
However, extensive chips may require that the entire diamond be re-cut. Recutting a diamond to repair a large chip can result in a substantial loss of weight, such as a third to a half of the carat weight or more. In addition, chips in a diamond might pose a durability risk just as a chip in a windshield has the potential to spread.
For that reason, we automatically reject any diamond that contains a chip.
My favorite type of inclusions are diamond crystals because they are just little diamonds that were trapped within a larger diamond crystal as it formed. Think of it like having tiny ice cubes trapped within a larger ice cube as it formed in your freezer. No big deal.
Some of our clients like to describe the diamond crystals within their diamond as baby diamonds. Which I suppose is basically what diamond crystal inclusions are for the most part.
Common types of diamond crystals are described as crystals, needles, clouds and pinpoints as defined below.
A pinpoint is a tiny diamond crystal that looks like a pinpoint of light when viewed under higher degrees of magnification. Pinpoint size diamond crystals are nothing to be concerned about. They look like sparkling specks of dust even at higher degrees of magnification.
It is quite common for pinpoint size diamond crystals not to be indicated on the plotting diagram. This is because their extremely small size makes them difficult to locate. Which is why you might see the comment “pinpoints not shown” under the “comments” section of a lab report.
The picture above shows a few normal sized diamond crystals as indicated by the red arrows and three pinpoint size diamond crystals which are indicated by the yellow arrows. As you can see, these diamond crystals are of no consequence even at this level of magnification.
Pinpoints are indicated on diamond grading reports as small red dots that are about the size of a pinpoint – go figure.
A “cloud” is simply a small group of pinpoint size diamond crystals. A “cloud” will usually consist of three or more pinpoint size diamond crystals located in close proximity.
Since smaller diamond crystals tend to be translucent most clouds are not a reason for concern. However, if a cloud covers a substantial portion of a diamond it should be looked at very closely. A cloud which is substantial in size might negatively impact the visual performance of a diamond. This is especially true of lower clarity diamonds or if the crystals are dark in color.
It is unlikely that a cloud of pinpoint size diamond crystals will affect the visual performance of diamonds which are VS-2 or higher in clarity. However, substantial clouds can be an issue in diamonds which are SI-1 and lower in clarity.
With that in mind, you’ll want to consider the extent of clouds within any diamonds you are considering. Clouds are indicated on diamond grading reports as circles or formations comprised of small red dots or pinpoints. If the plotting diagram indicates clouds or pinpoints that cover an extensive region within the diamond, consider asking me to look it over.
The two photographs above show a small cloud of pinpoint size diamond crystals as seen through our Gem Scope using a normal and diffused light source. This photograph shows slightly larger cloud of pinpoint size diamond crystals as seen using a normal light source.
As you can see, this cloud formation is more concentrated. Some people find this alarming. However, you have to remember that you’re looking at the diamond at about 35x magnification. It is highly unlikely that a cloud of this size will have any impact on visual performance.
Notice how the visibility of the inclusions varies depending on the light source being used to evaluate them.
Both of these examples show clouds which are minimal and which should not be a concern as they are primarily translucent and are not visible without substantial magnification.
The next two photographs show how extensive the clouds are within an SI-2 clarity diamond that I recommended a client not buy.
The cloud of pinpoint size diamond crystals within this SI-2 clarity diamond from James Allen is extensive. This photograph shows the cloud at about 20x magnification. From this vantage point it is easy to see that the cloud covers a substantial amount of the diamond.
Clouds which cover large areas of diamonds might affect light performance because the high concentration of pinpoints can interfere with the passage of light. Which is why I recommended that my client not purchase this diamond. Why risk it since there are so many other diamonds available, right?
The extensive cloud of pinpoints within this diamond becomes even more evident when viewed through an Ideal Scope. From this perspective, it's easy to see why I advised my client not to purchase this diamond.
The cloud of pinpoints clearly covers the vast majority of the diamond. It's pretty obvious that such a high concentration of pinpoints is likely to have a negative impact on light performance. While smaller clouds of pinpoints are barely visible even under higher degrees of magnification. Which is why it is important to evaluate every diamond on its own merits and take the individual inclusions into account as part of the evaluation process.
A “needle” is simply a diamond crystal which is long and thin in shape.
Whereas other diamond crystals might be more circular or asymmetrical in shape.
Needle shaped diamond crystals are no big deal. The series of photographs featured below show one diamond which contains several needle-shaped diamond crystals under the table facet of the diamond as seen through our Gem Scope at different levels of magnification and using different light sources.
Every once and awhile, I have the privilege of running across a diamond which contains some pretty cool looking inclusions. Such as the diamond crystals within this diamond which look kind of like a dragon.
It should be noted that diamond crystals are my favorite type of inclusions. Which makes sense because crystals are simply smaller diamonds which were trapped within the larger diamond crystal as it formed. As such, crystal-type inclusions are nothing more than diamond within the diamond. They tend not to pose any sort of durability risk and are generally of no consequence.
The diamond crystal within this diamond looks like a butterfly in flight or perhaps a fish. We usually photograph in black and white to make it easier to see the inclusions. However we shot this diamond in color because the diamond crystal was so prismatic.
Note that the diamond is white in color, but appears to have a slight brown tint in this photograph because of the light source. Don't you just love how the smaller diamond crystal inclusions create a bubble-like environment for this butterfly-fish shaped diamond crystal to swim around in?
Clearly. We're having too much fun projecting our imaginations on to these diamond crystals. Because we're pretty certain that this formation of diamond crystals looks like a magical fairy. What do you think?
All right, I'm going to level with you.
Comments around the office on this cluster of diamond crystals range from "It looks like a fairy" to "It looks like a hummingbird" and finally came down to "Hey, Led Zeppelin, The Song Remains the Same."
And that’s when we all decided that it was time to go home. In truth, it was a Friday afternoon and we were looking for an excuse to go home anyway. Obviously, we didn’t go home, because I’m still sitting here, typing. So on with the show!
The picture to the left shows the Led Zeppelin Fairy Hummingbird Diamond Crystal Formation (tribute band logo) as seen through our Gem Scope using 40x magnification. Which would make a regular size household ant look like Godzilla.
(More on that in a moment).
The diamond crystals within this 1.24 carat, F-color, SI-1 clarity, GIA Excellent cut round diamond from Blue Nile looks like a grasshopper to me in this clarity photograph. The diamond crystal is visible within the table facet in the relative one o’clock region.
This diamond has a pavilion angle of 40.6 degrees, which will provide a high volume of light return. While the 34.5 degree crown angle should produce a virtual balance of brilliance (white sparkle) and dispersion (colored sparkle) . The the 75% lower girdle facets should produce sparkle which is larger in size and bolder in appearance.
This is a photograph of a standard California household ant as seen through our Gem Scope using 20x magnification. I told you that the magnification used to clarity grade diamonds would make an ant look like Godzilla.
In case you're wondering why we'd photograph and ant at 20x magnification it was in response to an inquiry by a client about the size of a crystal within a diamond he was considering. I said that the crystal was about the size of a hair on ant's ass. To which he responded how big is that? The rest is history.
Be advised that crystal inclusions within the lab-grown diamonds are not necessarily the same as those within natural diamonds. Apparently some gemological laboratories are in the practice of referring to the cavity created when the diamond seed is vaporized to create the lab-grown diamond as a crystal.
It goes without saying that a cavity in the middle of a lab-grown diamond is not the same as a small diamond crystal absorbed by a larger diamond crystal as it forms.
Why a gemological laboratory would refer to a cavity as a crystal is beyond imagination. After all, an open space in the middle of a lab-grown diamond is nothing like a crystal inclusion. In addition, the practice of calling cavities crystals and lab-grown diamonds is bound to create confusion since they look nothing alike.
A “knot” is an included diamond crystal that extends to the surface of the diamond.
In other words, it is a diamond crystal which reaches the polished surface of a finished diamond.
This photograph shows a knot as seen through our Gem Scope using a diffused the light source which makes it easier to see this particular inclusion.
With proper lighting and magnification, you may be able to see the boundary between the knot and the diamond which contains it. Knots sometimes resemble raised areas on a facet surface or group of facets. Differences in the polish quality may be visible on the surface of the knot and the facet where it is located.
We increased the magnification substantially for this extreme close-up of the knot located within the table facet of this diamond. You might notice the similarity between this knot and the diamond crystals from before.
Remember that a knot is an included diamond crystal which extends to the surface of a diamond. Thus it is a crystal, but it also breaks the surface. As such, a knot has the potential to create a cavity if it is removed or knocked loose.
We generally reject diamonds which contain knots because of the potential durability risk.
A “feather” is essentially a minute fracture within the body of a diamond.
In response to the question which probably just popped into your head: I suppose that the labs use the term “feather” instead of calling it a fracture or a crack because it sounds more appealing.
Then again they don’t call a “cavity” a bubble so who knows what they're thinking.
Okay, that's not quite true. We do know why they refer to this type of inclusion as a feather. If you look closely at the inclusion highlighted by the red arrows in the photograph to the left you will see that it looks like a feather.
But keep in mind that not all feather inclusions will look like this one because every inclusion is unique and different. Which is why every diamond must be evaluated on its own merits.
Due to their very nature, all feathers within diamonds must be carefully evaluated.
Despite the fact that a feather is a fracture we will use the term feather to describe this type of inclusion to remain consistent with standard industry practice.
With that in mind, here goes:
Feathers are indicated on the plotting diagram on diamond grading reports as tiny red lines or hash marks.
Take a good look at the edges of the diamond indicated above and you will see a whole bunch of tiny red lines located along the edge of the diamond. Generally speaking, the presence of a few small feathers are not a reason for concern.
However, we feel that feathers which are substantial and/or which break the edge of the diamond have the potential to pose a durability risk and should be carefully evaluated.
Notice that we did not say that they should be avoided. We said that feather inclusions within a diamond should be carefully evaluated.
Which is something that I can help you with. Click on the blue button below and send me a link to the diamond details page or the diamond grading report number and I'll be happy to check it out for you.
The first thing to consider is whether the feather breaks the edge of the stone and if so to what extent?
Here’s a simple trick for determining whether a feather is likely to break the edge of a diamond.
Imagine that the plotting diagram pictured above is like a paper doll that children play with.
Then imagine that there is a dotted line running vertically down the middle of the upper and lower line diagrams:
Fold the plotting diagram for the lower half of the diamond on the right along the line so that it folds underneath the upper plot diagram on the left. From this perspective the tip of the kite shaped bezel facet in the 3 o'clock position on the upper half of the diamond will align with the tip of the pavilion main facet in the 9 o'clock position on the lower half of the diamond.
Now you have a two-dimensional representation of the position and extent of the feathers within this diamond.
Picture this. The two halves of the diagram are hinged together by an imaginary vertical line that is located between the two halves. If you used that line to fold the piece of paper in half so that the lower plotting diagram folded under the upper plotting diagram and aligned the two circles perfectly you would essentially have a two dimensional plotting diagram of the inclusions.
The side profile of the round brilliant cut diamond pictured to the left represents the two dimensional model created by folding the lower plotting diagram underneath the number planning diagram.
From this perspective you will see that most of the feathers indicated on the lower half of the plotting diagram line up with the feathers indicated on the upper half of the plotting diagram.
Which probably means that the feathers run the gamut of the stone from top to bottom through the girdle edge. Which might not be a good thing if the feathers are substantial because they could crack further if extreme pressure is placed upon the feather during the setting process.
The operative word here is “might” because we are not saying that it “will” happen because the odds are that the diamond will be set by a seasoned professional who should take the inclusions into account when setting the diamond.
However, we like to err on the side of caution and make you aware of the potential risks that feather inclusions within diamonds can present. That way you can take the feathers into account and make an informed diamond buying decision.
Your first instinct might be to. panic and avoid all diamonds that contain feather inclusions. However, the reality is that 99.99999% of feather inclusions within diamonds are of no consequence.
With this in mind, it is not necessary to avoid diamonds with feather inclusion types. Rather, it is only necessary to be aware that feathers within diamonds may present a durability risk. However, extremely unlikely, and simply take a moment to evaluate the inclusions and/or ask somebody like me to take a. look at the diamond.
The plotting diagram for this Black by Brian Gavin Diamond indicates that the primary inclusions consist of diamond crystals and feathers.
This is the Black by Brian Gavin Diamond that I selected for my sons engagement ring. Which might surprise you given everything you've just learned about feather inclusions with diamonds.
But remember that not all feathers within diamonds present a durability risk. Which means that the majority of feathers within diamonds are nothing to worry about. You just need to remember to take a look at the plotting diagram and clarity photographs and determine whether the feathers are extensive or not. In this particular instance, the feathers are of no consequence.
This is a perfect example of a feather that we're likely to avoid. You might not think that this feather looks bad from the top down perspective.
However, perspective is everything and the feather proves to be more substantial from the side profile:
Looking at the same feather from a side profile, we can see that the feather is substantial. The feather is located near the edge of the stone and runs the gamut of the stone from top to bottom through the girdle edge. A feather like this just might be a recipe for disaster or it might never become a problem.
This series of photographs shows the feather from the top down perspective. The second and third images show the feather as seen using a normal light source. The second and fourth photographs show the feather as seen using a diffused light source.
This series of photographs focuses on a feather which is located well within the body of the diamond. We do not think that this feather presents any sort of durability risk. In fact, a feather such as this would not concern us in the least.
The first picture shows the diamond as seen through our Gem Scope using a normal light source. We increased the magnification to 40x for the second image. We diffused the light source for the third picture to provide you with a different perspective of the feather inclusion.
At this level of magnification, it's easy to see why feathers are called feathers. Do you see how this inclusion looks just like the feather of a white bird? Perhaps those early GIA gemologists from the 1950s were onto something.
Here is another example of a feather that we do not feel presents any sort of durability risk. This feather is quite extensive and almost spans the entire width of the lower girdle facet. However, this feather inclusion is located well within the body of the diamond. In addition, it does not appear to exhibit any substantial stress points.
The first picture shows the location of the feather within the diamond from a side profile using a normal light source. The second picture shows the feather as seen using diffused light.
A “natural” is simply part of the original “skin” of the diamond that was left on the diamond rather than being removed during the cutting and polishing process.
What is the “skin” of a diamond? Take a look at this picture of uncut diamond rough. The rough exterior is what is considered to be the “skin” of the diamond.
Essentially it is part of the original diamond rough which is the uncut crystal from which a polished diamond is crafted. Most often a natural is left on a diamond because removing it would significantly reduce the weight of the finished diamond.
Most naturals are located along the girdle edge of a diamond. Although we have also seen natural inclusions located on minor facets. We consider most naturals to be a perfectly acceptable type of inclusion. However, you should carefully consider the location and extent of naturals during your selection process and determine whether they are acceptable to you or not.
As recent as twenty years ago, it was quite common to find naturals on the “four corners” of a round brilliant ideal cut diamond (the North, South, East and West sections) because they served as proof to the owner of the diamond cutting factory that the cutter had not removed any more of the diamond rough than necessary.
This series of photographs focuses on a natural inclusion which is located along the girdle edge of the diamond. The natural is located in alignment with the triangular upper girdle facet. The natural is indicated by the red arrows.
The first photograph shows the natural inclusion as seen through our Gem Scope from a top-down vantage point using a normal light source and 20x magnification. We diffused the light source with the second photograph which provides you with a different perspective.
The third and fourth photographs show diamond natural inclusion from the side profile using normal and diffused light sources.
The first picture above is perhaps one of the best photographs of a natural that we've been able to capture. The crystal structure of the natural is actually visible. This natural has been polished so that it appears crisper than most of the naturals that we see which are rough in appearance like the natural pictured in the second and third photographs.
An “indented natural” is simply a natural which is indented into the surface of the diamond. Indented naturals are often mistaken for chips by people who do not take the time to evaluate the inclusion under higher levels of magnification.
This is because it is sometimes possible to feel an indented natural with the tip of your fingernail if you run it along the girdle edge of the diamond. However, an indented natural inclusion is not a chip and it is nothing to worry about.
Of course, the extent and location of the inclusion must be taken into account during the evaluation process to determine whether the inclusion is acceptable.
This is an extreme close-up of an indented natural inclusion located along the girdle edge of a diamond as seen using 60x magnification.
From this vantage point it is easy to see how somebody might mistake and indented natural for a chip. However, if an indented natural were actually a nick, pit, chip, or a cavity, then it would be described as such on the key to symbols on the diamond grading report because those are different types of clarity characteristics.
Which makes perfect sense, right?
The girdle edge is the line which appears between the upper and lower halves of a diamond. There are several different ways to finish out the girdle edge of a diamond. The easiest is to leave the diamond “bruted” which is the result of the bruting process used to create the initial outline of a diamond before it is faceted.
Bruting the girdle edge of a diamond involves placing two pieces of diamond rough edge-to-edge in a machine. The edges of the diamonds beat against each other as they are spun in a circle at high speed.
The end result is the bruted satin finished edge pictured to the left. As you can see the bruted girdle edge of this diamond looks pretty rough.
I'm personally not very fond of the way the bruted girdle edge of a diamond looks. Probably because it does not look finished to me.
Sometimes the cutter spends a little time polishing the girdle edge of a diamond so that it appears smooth and shiny. Other times the cutter might add tiny facets to the girdle edge of a diamond as a finishing touch.
This is a photograph of the thin to medium, faceted girdle edge of a Brian Gavin Blue florescent diamond as seen at 70x magnification.
The girdle edge of this diamond has been laser inscribed with the logo for the Brian Gavin Blue florescent diamond collection and the diamond grading report number. If you're anything like me, then I'm sure that you will prefer this style of girdle edge.
Having the lab report number laser inscribed on the girdle edge of your diamond will make it easier for you to verify when dropping it off or picking it up from a jewelry store.
However, do not rely on the inscription alone because that can be forged by anybody with an inscription machine. With that in mind, you should always use the inscription in conjunction with the inclusions to identify your diamond.
Bearding or “dig marks” are small feathers and/or fractures and breaks located along the girdle edge of a diamond. Bearding is a side effect caused by the process of bruting a diamond. We reject for substantial bearding.
The first photograph above shows the inscription on the bruted girdle edge of this diamond. As you can see the girdle edge of the diamond. looks very rough and unfinished. In addition, the inscription on the girdle edge of the diamond looks rough.
The second photograph is an extreme close-up of the bruted girl edge of this diamond.
The third photograph shows the small fractures left along the girdle edge of the diamond by the bruting process as seen from the top down view.
As you can plainly see, the bruted girdle edge of a diamond leaves a lot to be desired. At the same time, it's not like you're going to spend a lot of time looking at the girdle edge of a diamond. Which means that the finish on the girdle edge of a diamond is largely a matter of personal preference.
As I'm sure you can imagine, we prefer a girdle edge which is polished and faceted. From our perspective it means something that the diamond cutter took the extra time and made the effort to finish the girdle edge properly.
You might see the comment “Internal Graining Not Shown” under the comments section on a diamond grading report.
The comment "internal grain lines not shown" is not a reason for concern.
Grain lines within a diamond are clarity characteristics which are rarely visible without the use of extremely high degrees of magnification.
The diamond pictured above contains internal grain lines which are not visible in this picture which was taken using 10x magnification which is the industry standard for diamond grading.
Internal Graining should not be considered an “absolute characteristic” because the visibility depends on the lighting conditions and the specific angle by which the diamond is being evaluated. It might be visible to an experienced diamond grader who is examining the diamond under laboratory conditions, but may never be detected by other people. Essentially internal graining refers to part of the grain structure of the diamond which was visible as a kind of transparent line to the grader.
The degree of the visibility of the grain lines will have an effect upon the clarity grade of the diamond and if no other clarity characteristics are present then the graining may be the basis for the clarity grade of the diamond. For instance, a diamond that contained small diamond crystals which by themselves would warrant a clarity grade of VS-1 might be graded as a VS-2 if internal graining were present.
However another diamond that did not contain the diamond crystals might be graded as VVS-2 if the grade is based upon internal graining and the comment “clarity grade based upon internal graining” would appear under the “comments” section of the lab report while nothing is indicated under the “keys to symbols” of the plotting diagram.
The round brilliant cut diamond picture to the left contains internal grain lines. The internal graining is not visible at 10x magnification which is the industry standard for diamond clarity grading.
Internal grain lines within a diamond can be very difficult to locate even with higher degrees of magnification. One of the reasons that internal grain lines are so difficult to locate is because they are translucent. Another reason is because internal grain lines look very similar to the edge of the facets of a diamond. However, it is easier to find them if they are located under the table facet.
Internal Graining should not be considered an “absolute characteristic” because the visibility depends on the lighting conditions. The angle from which you observe the diamond will also play a factor.
Internal grain lines might be visible to an experienced diamond grader who is examining the diamond under laboratory conditions, but may never be detected by other people even when using magnification.
Remember that internal graining refers to part of the grain structure of the diamond which was visible to a trained grader who was using higher degrees of magnification.
These photographs show internal graining under the table facet of this diamond at various degrees of magnification. The grain lines appear between the blue arrows. Notice how the visibility of the grain lines changes with the different light sources.
The comment on the lab report referring to “Surface Graining Not Shown” may sound kind of serious, but it really isn’t.
Surface graining is simply a small a transparent line that is part of the grain-like structure of the diamond crystal. Surface grain lines are basically the same as internal grain lines. However, surface grain lines appear on the surface of the diamond instead of being within the crystal structure of the stone. That makes a lot of sense, right?
Surface grade lines might appear across facet junction points. If the surface grain line is within the structure of the facet and not crossing over the facet line it will not be mentioned on the lab report because it is considered a characteristic of polish.
Most surface graining is so insignificant that we are rarely able to find it. When we are able to find surface graining it is because we are using higher degrees of magnification like 50 – 70x. That is substantially higher than the industry standard of 10x which is used for diamond clarity grading.
The facets of a diamond are just like tiny mirrors which serve to reflect light back up towards the surface of the diamond. It is quite common for inclusion to reflect multiple times within the diamond as the impression of the inclusion reflects off the facets.
As the inclusion reflects within the diamond it creates the illusion that the diamond is more included than it really is. This can be confusing because it may seem that inclusions are present in areas of the diamond where inclusions are not indicated on the plotting diagram.
This photograph is a perfect example of how the inclusions within a diamond can reflect and make it seem like a diamond is more included than it actually is.
Can you determine which of the white spots in this clarity photograph are the actual diamond crystals?
This kind of mirroring seems to be more apparent in clarity photographs and video which are taken at higher degrees of magnification than when diamonds are examined using 10x magnification.
This phenomenon can make it challenging to correctly identify the inclusions within a diamond. It also makes it difficult to accurately indicate the location of inclusions on the plotting diagram. Which might also make it difficult for you to verify that a diamond matches the report issued for it. However, this is something that an independent gemologist who has more experience grading diamonds will be able to assist you with.
The First photograph demonstrates how inclusions located on one side of a diamond (as indicated by the red arrows) can reflect to another location within the diamond (as indicated by the light blue arrows).
The second photograph shows the table facet of a diamond as seen at 40x magnification. The actual inclusions are indicated by the blue arrows while the reflections of those inclusions are indicated by green arrows.
The third photograph shows the inclusions within the diamond as seen using 70x magnification. Which makes it easier to see the source of the reflections. Reflections of the primary inclusions within a diamond are a byproduct of the facet structure which act like tiny mirrors.
As such, you should expect diamond inclusions to reflect into multiple locations within the diamond. The trick is trying to determine what is real and what is an illusion.
The term Twinning Wisps is used to describe the formation of inclusions which have been trapped within a twisted crystal plane. Twinning wisps are also known as inter-growth and represent one of the more complicated types of diamond inclusions.
Twinning wisps might include a variety of inclusions such as pinpoint size diamond crystals, fractures, crystals, feathers and clouds. The formation often looks like white striping within the diamond similar to cotton candy or stretch marks on skin.
Look closely at this photograph of this SI-2 clarity diamond and you will see the twinning wisps inclusions spattered throughout the stone.
The twinning wisps are most clearly visible along the edge of the table facet in the relative 2:30 and 8 o'clock regions. Look for the speckled spattering pattern of little black dots which are creating cloudiness in those areas.
Once you know you're looking for you will be able to see additional twinning wisps throughout the diamond in other locations. It is important to note that not all twinning wisp inclusions look this dramatic. In this specific instance the diamond crystals trapped within the twisted crystal planes are darker in color (as opposed to being translucent) which makes the inclusions more obvious.
This ASET Scope image provides us with an interesting perspective of the twinning wisps within this diamond. The contrast created by the different colors of the ASET Scope make it easier to identify the inclusions in some ways.
From this perspective it should be easier for you to see the twinning wisp inclusions under the table facet in the 2:30 and 8 o'clock regions.
Of course, the ASET Scope is not intended to be used to judge diamond clarity. But rather serves to help us determine how evenly light is reflecting throughout a diamond and where it is gathering light from within the room. With that in mind, we can see that light is reflected pretty evenly throughout this diamond. However the light pink under the table facet indicates a moderate amount of light leakage.
Refer to this article for more information on what the different colors of ASET mean.
This I-1 clarity pear-shaped diamond is heavily littered with twinning wisp inclusions and laser drill holes.
The twinning wisps within this diamond appear to be whiter because the diamond crystals contain within the twisted crystal planes are mostly translucent. However, the heavy concentration of twinning wisps within this diamond still make it look cloudy.
Twinning wisps are most often found in fancy shape diamonds such as pear shapes, heart shapes, and triangles because they are often fashioned from twinned diamond crystals. However, twinning wisps can appear within other diamond shapes as well depending on the quality of the diamond rough that was used to make the stone.
This heart shaped diamond contains a laser drill hole as indicated by the red arrow. The laser drill hole appears as a small white dot in the face-up position.
Diamond manufacturers sometimes laser drill diamonds to reduce the appearance of inclusions. The presence of the laser drill hole will be indicated in the key to symbols under the plotting diagram as "laser drill hole".
In some instances, diamond manufacturers may reduce the visibility of the laser drill hole by filling the channel with a clear substance. Diamonds which have been laser drilled and fractured filled are commonly referred to as "clarity enhanced" by retail jewelers. However, the Federal Trade Commission (FTC) requires the treatment to be disclosed in writing as "laser drilled and fractured filled".
The extent of the laser drill hole within this heart shaped diamond is more easily seen from the side profile. The most visible section of the laser drill hole appears between the two red arrows in the photograph to the left.
If you look closely you will see that a reflection of the laser drill hole inclusion is mirroring multiple times into other sections of the diamond.
This heart shaped diamond is laser drilled but not fractured filled. In the event that this diamond was clarity enhanced you might be able to see a reflection of lavender blue reflecting from the section that was laser drilled and fractured filled. Note that different diamond manufacturers use different colors when fracture filling diamonds. Thus, you might also see flashes of different colors in those sections.
Be advised that we automatically reject any diamond that has been laser drilled or fractured filled.
There are two types of etch channel inclusions that appear within diamonds. One type of etch channel is created by gas which escapes from the diamond crystal as it is being formed deep down in the mantle of the earth.
The other type of etch channel is left behind when the inclusions within diamonds are laser drilled to make them less noticeable.
I think that this photograph of a steaming geothermal crater located in Lake Waimangu Thermal Park provides a good example of the type of steam that might create natural etch channels in diamonds might look like.
Of course, the steam required to create etch channels within diamonds is probably escaping under a much higher degree of pressure than what we see here. It's an interesting concept that requires a bit of imagination. Work with me...
Laser drilling diamonds to eliminate inclusions and/or make inclusions less noticeable is nothing new. It is a technique that has been used for years, but that doesn't mean that I'm fond of the idea.
I generally try to avoid diamonds that have been laser drilled, fracture filled, clarity enhanced, or high-pressure heat-treated (HPHT) because I prefer diamonds to be the way nature intended.
The only way for us to know whether an etch channel is natural or man-made is to look for the phrase "internal laser drilling is present" in the comments section of the diamond grading report.
Etch channel inclusions are indicated on the plotting diagram as green squares surrounded by a red outline.
We added red arrows to the plotting diagram pictured to the left to help you identify the etch channels within this 1.51 carat, D-color, SI-1 clarity, GIA Excellent cut diamond from Blue Nile. The etch channels within this diamond appear to be natural because the phrase "internal laser drilling is present" does not appear in the comments section of the diamond grading report.
When you go to the diamond details page for this 1.51 carat, D-color, SI-1 clarity, GIA Excellent cut diamond from Blue Nile you will see a video of the diamond spinning in rotation. Click on the small photograph of the diamond located to the left of the video frame to see the diamond in the face-up position as pictured here.
From this vantage point you will be able to see the larger etch channel inclusion under the table facet and a few of the smaller edge channels located within the crown facets as indicated here by the red arrows.
It should be noted that the location of the inclusions in the clarity photograph may appear to be in different positions depending on the alignment of the diamond.
The red arrows indicate the etch channel inclusions within this 1.51 carat, D-color, SI-1 clarity, GIA Excellent cut diamond from Blue Nile. In the face of position the etch channel inclusions within this diamond look similar to diamond crystals.
However, the etch channel inclusions look more like laser drill holes from the side profile. Of course, etch channels within diamonds are neither crystals nor laser drill holes. Naturally occurring etch channels within diamonds are created by gas bubbles escaping the diamond while it is being created under high pressure.
The multi-colored ASET Scope image on the right provides us with a different perspective of the etch channels within this diamond. It also serves to identify light leakage under the table facet as indicated by the light pink and semi-translucent sections.
Be advised that we automatically reject any diamond that contains etch channels..
I hope you enjoyed reading this tutorial about diamond clarity characteristics (inclusions). It goes without saying that I probably could have made this section on diamond inclusions even longer and more detailed.
In fact, I could write an entire book on the subject of diamond clarity inclusions. However, the tips, tricks, and insight provided herein is what you really need to select a diamond with confidence.
At the same time, the constantly changing individual nature of inclusions can make selecting a diamond a daunting task. Which is why I invite you to take advantage of our Free Diamond Concierge Service. So that you will have the peace of mind of knowing that you made a good decision.