HomeDiamond Grading 2: Clarity Grading

17.2 Clarity grading

Diamond clarity is a term used to describe the absence or presence of flaws inside or on the surface of a diamond. A perfect stone with perfect clarity, or clearness, is rare, and most flaws that do exist in jewellery grade diamonds cannot be seen without looking at the gems through a jeweller's loupe.

Diamond is crystallised carbon, the diamond crystal growing very slowly in the interior of the earth. There are various phases in the growth of a diamond crystal, and during these phases pressure and temperature can vary causing irregularities, called inclusions. Inclusions may take the form of clouds, cavities, cracks or trapped non-carbon minerals. Inclusions can also have a positive purpose - they serve to identify a particular diamond and are an indication of the natural origin of a stone.

Apart from cracks and fissures, about twenty five different mineral impurities are know as inclusions in diamond, the most common being reddish garnet, brown spinel, green enstantite, black ilmenite and dark graphite.

Two of the most common inclusions are crystals and feathers. Crystals are merely minerals trapped inside the diamond. Feathers are breaks in the diamond. A professional grader must use a binocular microscope that magnifies the diamond ten times to locate these tiny characteristics. Then, evaluating the size, location, number and color of all inclusions and blemishes, a clarity grade is assigned.

Clarity is one of the two best-known factors in diamond pricing, along with colour. While the colour does affect a diamond's appearance, obvious inclusions (often called "flaws") may distract your recipient's eye from a stone's overall beauty. We usually recommend diamonds without inclusions or flaws that are visible to the naked eye. This avoids inadvertent negative feedback from friends and ensures the wonderful, lifelong enjoyment of your diamond.

To achieve this, stay well above the I-1 clarity grade. Clarity grades of SI2 or above are defined as flawless to the naked eye, but SI1 is safer in larger sizes. It's not necessary to go all the way up to IF (internally flawless) to get a beautiful diamond. From SI1 and above, diamonds will appear the same to the naked eye, differing only in the other factors of the 4 Cs: including Carat weight, Color and Cut.

Clarity greatly varies from one diamond to another, and no two are exactly alike. The Gemological Institute of America established standardised clarity grades for the diamond trade which are now used worldwide among dealers to help in trading and valuation. The GIA was the first to name graduations of inclusion in diamond.

The following chart gives an idea how each grade might look under a 10x loupe microscope:

 

Clarity Grades

Below are some simplified definitions of the various clarity grades set by the Gemological Institute of America (GIA).

GIA Clarity - FL/IF FL Flawless... Free from all inclusions and blemishes at 10x magnification
IF Internally Flawless... No inclusions visible at 10x magnification. Insignificant surface blemishes only
GIA Clarity - VVS1 VVS1 Minute (Very, Very Small) inclusions extremely difficult for a skilled observer to locate at 10x magnification.
GIA Clarity - VVS2 VVS2 Minute inclusions very difficult for a skilled observer to locate at 10x magnification.
GIA Clarity - VS1 VS1 Minor (Very Small) inclusions difficult for a skilled observer to locate at 10x magnification
GIA Clarity - VS2 VS2 Minor inclusions somewhat difficult to see at 10x magnification
GIA Clarity - SI1 SI1 Noticeable (Small inclusions) easy to see at 10x magnification
GIA Clarity - SI2 SI2 Noticeble inclusions very easy to see at 10x magnification and perhaps visible to the unaided eye.
GIA Clarity - I1 I1 (Imperfect) Obvious inclusions at 10x magnification barely detectable to the unaided eye
GIA Clarity - I2 I2 Obvious inclusions easy visible to the unaided eye.
GIA Clarity - I3 I3 Prominent inclusions extremely easy to see with the unaided eye and possibly affecting the durability of the diam
FL = Flawless -- no internal or external inclusions of any kind visible under 10x magnification to a trained eye, the most rare and expensive of all clarity grades


IF = Internally Flawless -- no internal inclusions visible under 10x magnification to a trained eye, but there may be some tiny external irregularities in the finish

VVS1 = Very Very Slightly Included 1 -- usually just one tiny inclusion visible only to a trained eye under 10x magnification; very difficult to locate even by an expert eye

VVS2 = Very Very Slightly Included 2 -- tiny inclusions visible only to a trained eye under 10x magnification; very difficult to locate by an expert eye

VS1 = Very Slightly Included 1 -- very small inclusions visible with 10x magnification; slightly difficult to difficult to see under a loupe with a 10 power magnification.

VS2 = Very Slightly Included 2 -- several very small inclusions visible with 10x magnification; slightly difficult to difficult to see under a loupe with a 10 power magnification.

SI1 = Slightly Included 1 -- small inclusions visible with 10x magnification

SI2 = Slightly Included 2 -- several small inclusions visible with 10x magnification

SI3 = Slightly Included 3 -- inclusions that may be visible to the naked eye for a trained observer

I1 = Included 1 -- flaws that are visible to the naked eye

I2 = Included 2 -- many flaws clearly visible to the naked eye that also decrease the brilliance

I3 = Included 3 -- many flaws clearly visible to the naked eye which decrease the brilliance and compromise the structure of the diamond, making it more easily cracked or chipped

SI3

Outside of the GIA Diamond clarity scale is a grade you may have seen called SI3. The Rap Sheet(Rapaport Diamond Report), a Trade Publication, honours the SI3 grade which is given out by EGL, the European Gemological Laboratory. It is described as a split between the SI2 and I1 clarity grade.

If you really want to *see* what the differences in the Clarity Grades look like under magnification, there is an excellent book by Gary Roskin called Photo Masters for Diamond Grading. It provides photographs and explanations of different Clarity Grades and the inclusions causing them.

GIA Clarity Grading System

Considerations in grading the clarity of a diamond include the type of stone, point size and the location of inclusions. Inclusions that are near to, or break the surface, may weaken the diamond structurally, therefore reducing its value significantly. On the other hand, it may be possible to hide certain inclusions behind the setting of the diamond (depending on where the inclusion is located), thus minimizing any negative impact of the inclusion.

 

Diamond Clarity Grade Inflation

A fairly common practice in the jewelry trade is grade-inflation or "grade bumping." According to the Federal Trade Commission's (FTC's) Jewelry Guides, a diamond must be within one clarity grade of its advertised amount at the time of sale. If a jeweler sells a diamond that has an actual grade of VS-1, he or she could legally sell it as a VVS-2.

Main gradeSubgrade Short grade explanation
Loupe clean FL Flawless Internally and externally flawless when examined with a loupe
IF Internally Flawless Internally flawless
VVS VVS 1 Very very slightly included
(high end-close to IF)
Very, very small inclusions may be visable when examined with a loupe but the inclusions are not on the table
VVS 2 Very very slightly included
(low end-close to VS 1)
Very, very small inclusions may be visable when examined with a loupe
The distincion between VVS 1 and VVS 2 is only made for stones above 0.5 ct
VS VS 1 Very slightly included
(high end-close to VVS 2)
Very small inclusions are present that are hard to see with the loupe but the inclusions are not on the table
VS 2 Very slightly included
(low end-close to SI 1)
Very small inclusions are present that are hard to see with the loupe
SI SI 1 Slightly included
(high end-close to VS 2)
Small inclusions are easily observed with the loupe but the inclusions are not on the table
SI 2 Slightly included
(low end-close to I 1)
Small inclusions are easily observed with the loupe
I I 1 Imperfect 1 Inclusions are hard to observe with the naked eye, but easily with the loupe
I 2 Imperfect 2 Inclusions are hard to observe with the naked eye but occur in multiple sites
I 3 Imperfect 3 Inclusions are very easily observable with the naked eye and interfere with the brilliance of the stone


17.2.1 Define imperfection

There are several different types of blemishes, or flaws, that you might see on the surface of a diamond. Some diamond blemishes are a natural part of the gem and others occur either when the diamond is cut and polished or while you are wearing it.

Surface blemishes can affect diamond clarity and value, but many blemishes have little or no affect on a diamond's appearance.

Scratches are usually fine surface lines that can be polished away, but the diamond must be removed from its setting in order to do that.

Nicks are areas where a portion of the diamond has chipped away. Small nicks are sometimes repaired by polishing them to create an extra facet. If too many extra facets are created in order to remove blemishes, they can have a negative impact on the diamond's appearance and value.

Pits are holes in a diamond's facet. Some pits aren't noticeable, but a pit on the diamond's table facet is more likely to be visible and will affect the diamond's clarity grade. Shallow diamond pits can sometimes be polished away.

natural is a portion of the diamond's original rough surface that hasn't been polished. Naturals are sometimes left along a diamond's girdle if doing so allows the cutter to produce a larger carat weight stone. Naturals don't normally impact the diamond's clarity grade if they are present only on the girdle.

trigon is a natural that looks like a small triangle. A trigon sometimes looks like series of triangles within triangles.

Polishing lines are markings that occur during the cutting and polishing process. Their affect on the diamond's looks and value depends on where they are. Polishing lines on the pavillion aren't as noticeable as lines in other areas.

17.2.2 Internal blemish

Internal Diamond Inclusions

  • Carbon - Tiny black spots caused by undigested carbon inclusions (natts).
  • Clouds - Cloudy grouping of tiny pinpoints that may not resolve at 10X Magnification.
  • Feathers - Cleavage planes or internal fractures that have the appearance of feathers.
  • Grain Center - Concentrated area of crystal growth that appear light or dark.
  • Internal Graining - Irregular crystal growth causing internal distortions, waviness, haze.
  • Needles - Rutile-like needle shaped inclusions.
  • Pinpoints - Minute crystals within the diamond that appear white.
  • Pique - Garnet or other Included gem stones
  • Twinning Wisps - Inclusions resulting from crystal twining during growth.


17.2.3 External blemish

Many exterior flaws are the result of the cutting and polishing process.

External Diamond Inclusions

  • Bearded Girdles - Fine cracks, chips, fringing, or feathers along the outer edge of girdle.
  • Bruising - A percussion mark caused by impact.
  • Cavities - An indentation resulting from a feather or damage during polishing.
  • Chips - Damage usually occurring on the sharp edge of a facet.
  • Knots - An inclusion that penetrates the surface, appearing as a raised area.
  • Indented Naturals - A natural indentation that was not removed by polishing.
  • Filled Fractures - Fractures that have been artificially filled.
  • Pits - Dislodged pinpoint inclusions at the surface.
  • Surface Graining - Visible surface lines caused by irregular crystallization during formation.

Human Caused Surface Blemishes

  • Abrasions - Whitish haziness along the junction of facets caused by wear.
  • Nicks - Small chips at facet junctions.
  • Scratches - Grinding Wheel Marks of scratches from contact with other diamonds.
  • Burn Marks - Surface burning from heat buildup during polishing.

17.2.4 Plotting clarity characteristics

Consider the Location of Diamond Flaws

It's important to consider where a diamond's flaw is located in relation to the stone's cut, because some flaws are more noticeable when positioned in specific areas.

Since no two diamonds are alike, the flaws provide an important road map that may help us identify our property.

GIA Clarity Grading System:

 

It is important to be know that inclusions and blemishes are much more difficult to see in the actual diamond than they usually appear as drawn on the diamond plot.

FL: (Flawless) Flawless diamonds show no inclusions or blemishes of any sort when examined by a skilled grader under 10X binocular magnification

IF: (Internally Flawless) No inclusions, and only insignificant surface blemishes. Normally, what separates IF from FL diamonds are characteristics that can be removed by very minor re-polishing.

VVS1 and VVS2: (Very Very Slightly Included) Minute inclusions that are difficult for even a skilled grader to see under 10X binocular magnification. In VVS1, they are extremely difficult to see, visible only from the pavilion, or small and shallow enough to be removed easily by re-polishing. In VVS2, inclusions are still difficult to see.  Typical inclusions: scattered pinpoints, taint clouds, slightly bearded girdles, internal graining, and tiny feathers, chips and bruises.

VS1 and VS2: (Very Slightly Included) Minor inclusions ranging from difficult to somewhat easy for a trained grader to see when examined using 10X magnification.  Typical Inclusions: small included crystals and feathers, distinct clouds, and groups of pinpoints.

SI1 and SI2: (Slightly Included)Noticeable inclusions that are easy (SI1) or very easy (SI2) to see when examined by a trained grader using 10X magnification.  Typical inclusions: small included crystals, clouds, feathers.

I1,12 and I3: (Imperfect) Obvious inclusions that are often easily eye-visible face up; in I3 they may threaten durability.  Typical inclusions: large included crystals and feathers.

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