Diamond Clarity Chart

Because they are formed deep within the earth, under extreme heat and pressure; virtually all diamonds contain "birthmarks"; small imperfections inside the diamond (called inclusions), or on its surface (called blemishes). Clarity refers to the degree to which these imperfections are present. Diamonds which contain numerous or significant inclusions or blemishes have less brilliance because the flaws interfere with the path of light through the diamond.

The position of an inclusion affects how easily it can be seen. Diamond cutters make every effort to cut a stone so that inclusions are not visible through the table of the finished diamond. The preferred position for inclusions is under the bezel facets or near the girdle because they are harder to see there.

Almost all diamonds are graded for clarity using the 11 point diamond clarity scale created by the GIA, including diamonds which were not actually graded by GIA (every Lumera Diamond is GIA certified). In grading diamond clarity, the GIA considers the number, size, color, reflectivity, and position of every flaw visible under 10x magnification.

Below is the GIA diamond clarity chart with definitions, accompanied by further explanatory comments from Lumera:

GIA Diamond Clarity Scale

Questions about clarity or other aspects of a diamond? Ask a diamond consultant for answers. A consultant will answer any questions you have, and if you like, search for diamonds on your behalf that match your criteria. A consultant can personally review a diamond, and give you a report on it's clarity or other details. chat online, or email consultant@lumeradiamonds.com.

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Diamond Plot

Because a photograph cannot capture the subtleties of clarity, GIA uses a diamond plot to map a diamond's interior and exterior flaws. A diamond plot is a graphic representation of every flaw that affects the overall clarity grade. The flaws are found under 10x magnification by a skilled grader.

GIA Diamond Plot
Example GIA Diamond Plot: The Key To Symbols section
shows the flaws in order of severity

While the plot shows the type and position of each flaw, the actual visibility of the flaw is communicated in the diamond Clarity Grade itself (i.e. two diamonds may have very similar plots, but very different Clarity grades, reflecting the actual severity and visibility of the recorded flaws).

Besides the plot, there is also a comment section on the certificate where additional clarity characteristics are often noted. These are usually too minor to be reflected in the plot itself. Between the plot and the comment section, all inclusions visible under 10x magnification are accounted for.

A note of caution:

A diamond plot does not reproduce the actual appearance of a diamond. For SI1 or lower grades, do not assume that a relatively clean plot indicates that there are no flaws visible to the naked eye. Often, a plot may carry only one or two markings, but these are so severe that they warrant a lower overall clarity grade.

By the same token, a cluttered plot may not mean the diamond is visually flawed. The diamond may in fact be flawless to the naked eye, since no single inclusion is severe enough to be seen (even though the cumulative effect of the flaws might warrant a lower clarity grade). When in doubt, speak to a diamond consultant, who will gladly review a diamond on your behalf.

Common inclusions and blemishes, as they are represented on the GIA diamond plot, are illustrated below. GIA uses the color green for surface blemishes, and red for internal inclusions. Sometimes the nature of the inclusion (if it reaches the surface, for example) calls for the use of both green and red. The color black is used to convey extra facets.

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The standard GIA Grading Report includes a diamond plot, the abbreviated GIA Dossier (often used for diamonds under 1 carat) does not.

A note of caution:

Before and After: Fracture Filled Diamond
Before and After:
Diamond Fracture Filling

Approximately 1 in 3 diamonds sold has been treated or "enhanced" in some way. A variety of techniques exist to artificially improve the natural clarity of a diamond. By drilling a pathway to an internal inclusion with a laser beam, acid can be poured into the tunnel to bleach the inclusion. The laser tunnel appears as a tiny white dot when viewed from the top of the diamond (where the drilling was performed), but as a long white line when viewed from the side. In addition, fractures in a diamond can be filled with a clear glass-like material, making them less visible. GIA will not certify diamonds which have been fracture filled.

While laser drilling and fracture filling are used to improve a diamond's clarity, high pressure / high temperature (HPHT) treatments are used to improve color by removing brown colorations from the diamond. HPHT involves placing the diamond in a pressure vessel and applying extremely high pressure and temperature. This environment mimics the conditions the diamond crystal was originally formed under. The effects of HPHT are permanent, and the presence of the treatment is very difficult to detect. GIA will certify a HPHT diamond, but will note the presence of the treatment on the diamond's certificate.

Any treatment or "enhancement" made to a diamond lowers its value. Lumera does not sell diamonds that have been treated in any way, including HPHT.

Buying Tip:

If you cannot tolerate imperfections, even those you cannot see, choose a VVS2 or better diamond. About 10% of all diamonds sold fall into this category.

The most popular range is the VS1-VS2 diamond. These diamonds appear flawless to the naked eye, and are a fraction of the price of a truly flawless diamond. Almost half of all diamonds purchased fall into this range.

The next most popular range is SI1, where the inclusions are usually not significant enough to impact the appearance of the diamond for the casual observer. Often, customers will opt for this clarity range in exchange for a higher cut or color grade. This combination often results in a beautiful, lively diamond with imperfections detectable only upon close inspection. In diamonds under 1 carat, the same can be said for an SI2 grade. In diamonds over 1 carat (where clarity is more important, and SI2 inclusions are often easier to detect), an SI2 is often half the price of a VS1 diamond. About one third of diamonds sold fall into the SI1-SI2 range.

If you are primarily concerned with size and price, I1 may be your best option. While the inclusions are visible to the unaided eye, many customers find it to be well worth the sacrifice for what it affords in size.

The larger the diamond, the easier imperfections are to detect; therefore Clarity becomes more important. For diamonds over 2 carats, a clarity grade of VS2 or higher is the safest bet for avoiding any signs of visible inclusions. In diamonds between 1 and 2 carats, clarity grades of SI1 or better will not have inclusions easily visible to the naked eye. In diamonds under 1 carat, clarity should be considered the least important of the traditional 4 Cs.

Brilliant-cut diamonds (such as round, princess, cushion, oval, pear, and marquise) hide inclusions better than step cuts (emerald, asscher). When purchasing a step-cut, move up one clarity grade (e.g. purchase a VS2 instead of an SI1 if you desire the lowest grade that has no visible inclusions).

If, while shopping for a diamond, you are ever given a clarity range (e.g. SI1-SI2) as opposed to a specific clarity grade, the diamond is not certified by GIA. The seller is only estimating the diamond's clarity using GIA terminology.

Visit the Lumera Diamond Buying Guide for additional tips and advice.