Clarity Characteristics

The “Clarity Characteristics” section on gemological lab reports indicates the type of inclusions contained within the diamond described by the lab report.

The term “clarity characteristic” refers to the inclusions within a diamond which are the basis for the clarity grade assigned to the diamond. This section of our web site is intended to be used as a way for you to become more familiar with the basic types of inclusions which may be present within a diamond. The examples are intended to be just that “examples” and are not absolute indications of what each inclusion type may look like because each inclusion type may take on many different forms and still be a basic type of inclusion. Be sure to review our page on Degrees of Magnification before reading this page so that you have a basis as to the degrees of magnification that were used to capture the images displayed within this article.

Note that most gemological laboratories only indicate the primary inclusions which are considered to be the basis for the clarity grade and do not attempt to indicate all of the inclusions within the diamond, thus it is common to see comments like “additional pinpoints (or clouds) not shown” under the “Comments” section of the lab report. The comment “additional pinpoints (or clouds) not shown” simply means that there may be small pinpoint size diamond crystals or groups of pinpoint size diamond crystals (this formation is known as a cloud) present within the diamond which are not indicated on the plotting diagram by a symbol indicating that inclusion type or location.

The key to determining the type of clarity characteristics within a lab graded diamond is contained within the plotting diagrams which appear on the lab report. 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. Inclusions will be indicated on the section of the plotting diagram where the inclusion is located and not necessarily where it is visible from. Thus an inclusion may be indicated in the lower half of the diamond as is feather indicated by the green arrow in the diagram provided, but may be apparent from a top down view because the facets of a diamond are essentially tiny windows that make it possible to see inclusions from a variety of vantage points.

Beneath the plotting diagram on a GIA diamond grading report there is a “key to symbols” which indicates the type of inclusions contained within the diamond. On AGS graded diamonds the key to symbols is usually located on a flap which is folded beneath the report when it is placed in its folder.

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To align the top and bottom portions of the plotting diagrams, imagine a dotted line running vertically between the two halves. If you were to fold the bottom half (right side) of the plotting diagram on the dotted line and fold it under the top half, that is the correct alignment for the stone. Thus the three o’clock position of the bottom plotting diagram aligns correctly with the nine o’clock position of the upper plotting diagram. With this alignment in mind, it is easy to determine the proximity of inclusions plotted on the upper half of the plotting diagram with those that might be indicated on the lower half and vice versa.

Chips on Diamonds:

Photograph of chipped culet on princess cut diamond, AGS 0009139406tip4a seen at 60x magnificationWith 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 are nouns. A chip in the surface of a diamond most often occurs as the result of a slight impact. Most chips 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. Extensive chips may require that the entire diamond be re-cut which usually results in a more substantial loss of weight, such as a third to a half of the carat weight or more.

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Photograph of chipped culet on princess cut diamond, AGS 0009139406tip4a seen at 60x magnificationThe chips pictured here are located on the culet (bottom point) of the diamond. They are most likely the result of a downward impact on the diamond when it was being worn or it might have occurred during the setting process. People often say that they want their diamond set as low as possible in the prongs, but chips like this are the reason we like to leave a little space between the bottom point (culet) of the diamond and the base of the head. The space has the potential to act as a pad that helps to allow for an unexpected downward impact and reduces the chance of accidentally chipping the diamond during the setting process.

The diamond tends to press down a little when the prongs are being crimped into place. A small chip like this does not really have an effect upon the durability of the diamond and can be easily removed without incurring a significant loss of weight.

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Diamond Crystals:

Diamond crystals are our favorite type of inclusion because they are essentially nothing more than small 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” and we suppose that’s kind of what they are. Common types of diamond crystals are described as crystals, needles, clouds and pinpoints as defined below.

Pinpoints: a “pinpoint” is simply a tiny diamond crystal that looks like a pinpoint of light when viewed under higher magnification such as 20x and higher. Pinpoints are often not indicated on the plotting diagram on diamond grading reports because they can be difficult to locate, thus 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. Pinpoints are indicated on diamond grading reports as small red dots that are about the size of a pinpoint – go figure.

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Clouds of Pinpoints:

gia13288022gs3cA “cloud” is nothing more than a small group of pinpoint size diamond crystals. Generally speaking, a “cloud” will 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.

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gia13288022gs3dHowever if a single cloud appears to cover a third or more of a diamond it should be looked at very closely and the effect that it might be having upon the visual performance of the diamond must be considered. Clouds are indicated on diamond grading reports as circles or formations comprised of small red dots or pinpoints.

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gia13288022gs4cThe two photographs above shows a small cloud of pinpoint size diamond crystals as seen through our Gem Scope using a normal and diffused light source. This photograph (left) and the one below show a more extensive cloud of diamond crystals as seen through our Gem Scope using a normal and diffused light source.

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gia13288022gs4dNotice how the visibility of the inclusions vary 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.

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Needle Shaped Diamond Crystals:

A “needle” is simply a long, thin, diamond crystal. Instead of being circular in shape, it is long and thin, like a needle. Get it?  No big deal. The series of featured below show one diamond which contains several needle shaped diamond crystals which are located within the table facet of the diamond as seen through our Gem Scope at different levels of magnification and using different light sources.

Cool Diamond Crystals:

Some diamond crystals are more interesting than others… This one reminded us of a dragon.

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, but we shot this diamond in color because the diamond crystal was so prismatic! Note that the diamond is white in color, but photographed with a slight brown tint, this is due to the lighting conditions and is just one of those things that you learn to overlook. But how cool is this inclusion?

This picture which was taken at 20x magnification shows a group of diamond crystals which are grouped together to create this formation kind of resembles a fairy which is kind of cool, see the blue arrow. Comments around the office ranged from “it looks like a fairy” to “it looks like a hummingbird” and finally it 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 next picture shows the Led Zeppelin Fairy Hummingbird Diamond Crystal Formation (tribute band logo) as seen through our Gem Scope using 70x magnification (which would make a household ant look like Godzilla).

blue-nile-gia-excellent-cut-round-diamond-reviews-1209446670-cool-diamond-crystals-niceiceThe 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; and the 34.5 degree crown angle will produce a virtual balance of brilliance (white sparkle) and dispersion (colored sparkle) while the 75% lower girdle facets should produce broad spectrum sparkle, which is larger in size.

Blue Nile generally does not provide diamond clarity photographs for the diamonds represented by their virtual inventory, but sometimes I can find them within the inventory of the various diamond cutters that they work with, so feel free to ask me to check out any diamonds that you might be considering from them. Just send me a link to the diamond, or the stock number which usually looks something like “LD06149751” and I’ll see what I can find out about the diamond for you.

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Knots:

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. 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.

The first picture above shows a knot as seen through our Gem Scope using a normal light source, we diffused the light source for the second picture to provide you with a different perspective of the inclusion.

We increased the magnification substantially for these extreme close-up’s of the inclusion as seen through our Gem Scope using a normal and diffused light source.

Feathers:

A “feather” is essentially a tiny fracture. In response to the question which probably just popped into your head, we suppose that the labs use the term “feather” as opposed to “crack” because it sounds a whole lot more appealing, but then again they don’t call a “cavity” a bubble so who knows… For the sake of consistency, we’re going to refer to the term “feather” in our description because that is the standard industry term used to describe small fractures within a diamond. That said, 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 reason for concern, however we feel that feathers which are substantial or which break the edge of the diamond may present a future durability risk to the diamond and require extensive evaluation

Notice that we did not say that they should be avoided, we said that they require extensive evaluation. The first thing to consider is does the feather break the edge of the stone?

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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 a paper doll, fold plotting diagram for the lower half of the diamond under the upper plotting diagram for the diamond and you have a kind of two dimensional representation of the position and extent of the feather within the diamond. No doubt we’re losing you. 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.

Do that with the example of the plotting diagram pictured above and you should come to the realization 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. And that usually means that the feathers run the gamut of the stone which might not be such a great thing if the feather is substantial because it “might” crack further if undue pressure is placed upon the feather during the setting process. The operative word here is “might” we are not saying that it “will” happen because the odds are that the diamond will be set by a seasoned professional which will take the inclusion into account when setting the diamond, but we like to err on the side of caution and mention the possibility.

This is a perfect example of a feather that we would avoid. It probably doesn’t look that bad from a top down perspective, but perspective is everything. As you will discover in the next set of pictures, the feather looks much different from a side profile.

Viewing 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 facets. A feather like this just might be a recipe for disaster.

This series of photographs focuses on a feather which is located well within the body of the diamond and thus we feel it does not present any sort of durability risk. 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 using 40x magnification. We diffused the light source for the second picture to provide you with a different perspective of the inclusion. At this level of magnification, the feather is a perfect example of why a feather is called a feather – notice how it looks just like a white feather off of a bird.

Here is another example of a feather that we do not feel presents any sort of durability risk… This feather is larger than most, but is located well within the body of the diamond and does not exhibit any substantial stress points. The first picture shows the location of the feather within the diamond from a side profile. The second and third pictures are close-up’s of the feather as seen through our Gem Scope at 30x magnification.

Naturals & Indented Naturals:

Natural: A “natural” is simply part of the original “skin” of the diamond that was left on the diamond instead of 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 reduce the weight of the finished diamond unnecessarily.

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Most naturals are located along the girdle edge of a diamond although we have also seen them on minor facets from time to time. We consider most naturals to be a perfectly acceptable type of inclusion, but give careful consideration to the location and extent of naturals during our selection process to determine whether they are acceptable to us 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 which is located along the girdle edge of the diamond in alignment with the triangular upper girdle facet, the natural is indicated by the red arrow. The first picture shows the 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 and increased the magnification to 40x for the second picture.

The first picture featured above is perhaps one of the best photographs of a natural that we have been able to capture, the crystal structure of the natural is actually visible. This natural has been polished so that it appears more crisp than most of the naturals that we see which are rough in appearance like the natural pictured in the second photograph.

Indented Natural:

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… Once again, the extent and location of the inclusion must be taken into account during the evaluation process to determine whether the inclusion is acceptable.

The photographs above show a variety of indented naturals as seen through our Gem Scope at higher levels of magnification. Note that if an indented natural were actually a nick, pit, chip or cavity, that it would be described as such on the key to symbols as those are different types of clarity characteristics.

Girdle Finish: “Satin” or “Bruted”

The girdle 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 which shapes the initial shape of a diamond before it is faceted. Basically two round brilliant cut diamonds are placed in a machine so that the girdle edges of the diamonds will rub against each other as they are spun in a circle and the result is a kind of satin finished edge as shown in the picture above. This particular diamond is also inscribed with the report number for the corresponding GIA lab report to assist with identification.

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Girdle Finish: Polished & Faceted

Sometimes the cutter spends a little time polishing the bruted edge of a diamond so that it appears smooth and shiny and other times they add tiny facets to the girdle edge of a diamond as a finishing touch like the second picture which shows a faceted girdle edge which is inscribed with the AGS lab report number. Bruted, polished, or faceted, the type of girdle finish really doesn’t make a difference to us provided that the finish is done properly. The girdle edge of most diamonds is so small that the type of finish makes little difference. Personal preference, that’s about it.

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“Bearding” on the Girdle Edge:

Bearding or “dig marks” are small feathers or breaks along the girdle edge of a diamond that are caused by the bruting process. We reject for substantial bearding.

Grain Lines: Internal Graining:

The comment on a lab report indicating “Internal Graining Not Shown” should not be reason for alarm because it refers to a clarity characteristic which is usually not readily visible without the use of extremely high 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 experience 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” by the plotting diagram.

This series of photographs shows the very subtle effect of internal graining as seen within a diamond we purchased for inventory at various degrees of magnification. Notice how the internal graining is not readily visible in the first picture which was taken using a magnification level of about 20x. The internal graining is barely visible in the next photograph which was taken of the table facet at about 40x magnification, the grain line appears as a kind of translucent line as indicated by the light blue arrows.

Grain Lines: Surface Graining:

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 essentially a transparent line that is part of the grain of the diamond which happens to be visible across a facet junction. It is essentially the same thing as Internal Graining but it resides on the surface of the diamond instead of being within the crystal structure of the stone. If the surface grain line were within the structure of the facet and not crossing over the facet line it wouldn’t be mentioned on the lab report because it would be considered a characteristic of polish.

Most surface graining is so insignificant that we are rarely able to find it and when we do it is because we are using extensive magnification like 50 – 70x which is substantially higher than the industry standard of 10x which is supposed to be used for diamond grading. Take a look at the first picture above which was taken using 20x magnification (industry standard for diamond grading is 10x). Can you see the surface graining? Probably not. We kicked things up to 40x for the second picture which highlights the surface graining with blue arrows to make it easier for you to identify. In the case of a diamond graded as Internally Flawless in clarity, as a general rule it is likely that the diamond may have been graded as Flawless instead of Internally Flawless if the surface graining were not present.

Reflections of Inclusions:

The facets of a diamond are essentially tiny mirrors which serve to reflect light back up towards the surface of the diamond. Quite often these mirrors will also cause an inclusion to reflect within the diamond so that it appears more numerous than it really is and so that it appears to exist in areas of the diamond where it was not. This phenomena can make it quite challenging to correctly identify the inclusions within a diamond, represent the position of inclusions accurately and sometimes to even locate a specific inclusion based on the plotting diagram provided on the lab report.

The first picture provided above is a perfect example of the phenomena of inclusions which reflect, click on the thumbnail to view the full size picture and try to figure out which of the white specks is the real diamond crystal. The second picture is an excellent example of 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 third picture shows the table facet of a diamond as seen at 40x magnification with the actual inclusions indicated by blue arrows and the reflections of those inclusions indicated by green arrows.  The fourth picture shows the inclusions within that diamond at 70x magnification so that you can see the source of the reflections. Reflections within a diamond are essentially a product of the design and facet structure of a diamond and are to be expected, the trick is trying to determine what is real and what is illusion.

Twinning Wisps (Intergrowth)

The term Twinning Wisps, also known as Intergrowth, is used to describe the formation of inclusions which have twisted together within a twinning plane. The formation 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 stretch marks on skin. 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 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.