Clarity ratings are determined by the amount and visibility of inclusions in a diamond. Inclusions consist of tiny pinpoints, markings, and clouding which affect the overall appearance of the diamond. There are two types of flaws within a natural diamond: inclusions and blemishes. Inclusions refer to the internal flaws of a diamond and blemishes refer to external or surface flaws.
In general, diamonds with fewer inclusions and blemishes will have a better clarity rating. This increases their brilliance and value. Diamonds with clarity grades VVS1 through SI2 have slight inclusions that may be visible to varying degrees under 10 x magnifications, but are generally not visible to the unaided eye. Diamonds with I1 clarity ratings contain inclusions that are easily seen under 10 x magnifications and may be visible to the unaided eye. Diamonds with I2 and I3 clarities have major inclusions that are easily seen without magnification.
Often times the inclusions are microscopic diamonds that were absorbed by the larger crystal before the diamond was carried to the surface of the Earth. The quantity, size, color, location, orientation, and visibility of inclusions all affect the final clarity grade of a diamond. Diamonds with no or few inclusions are considered particularly rare and highly valued.
Diamond Clarity Scale.
||Flawless: No inclusions under 10x. A stone that is completely flawless. This is an extremely rare find.
||Internally Flawless: No internal imperfections. A stone that has no internal flaws at all but does have surface flaws. Also, an extremely rare find.
||Very Very Slightly Included: A stone with very minute internal inclusions that are extremely difficult to see under a 10X magnification.
||Very Slightly Included: A stone with very minor internal inclusions that range from difficult to somehwat easy see under a 10X magnification.
||Slightly Included: A stone that has imperfections visible under X10 magnification and may be visible with the unaided eye.
||Included: A stone that has significant inclusions most often visible with the naked eye. Inclusions of this level drastically bring down the diamonds value.
Eye-Clean and Non Eye-Clean Diamonds
As mentioned, when diamonds are formed, deep underground and under extreme pressure and heat, imperfections in the crystal structure can form and mineral impurities become trapped inside the stone. The size of these impurities and imperfections determine the clarity grading of a diamond. Diamonds without such impurities are very rare.
Eye-Clean and Non Eye-Clean Diamonds.
An "eye-clean" diamond is one that has no imperfections visible to the unaided eye. They offer excellent value, being much less expensive than flawless (FL) or internally flawless (IF) diamonds, which are extremely rare and therefore command a higher price.
Diamond Clarity Scale and Eye-Clean and Non Eye-Clean Diamonds.
Imperfections in diamonds graded Slightly Included (SI) are often not visible to the unaided eye, making them excellent value for money, however the location of the inclusion is important. Therefore, it always advisable to speak to a diamond and jewellery consultant to check that the stone is eye-clean, if you're considering a diamond of this clarity grade.
Expert Tip 1
As magnification is needed to see impurities in diamonds witha VS1 grading or higher, a choice of VS1 or higher is a subjective quality choice which goes beyond what can be seen to the unaided eye. Larger Diamonds with these higher grades are much rarer and therefore command greater pricing premiums, and also tend to perform better as an investment.
Expert Tip 2
Although SI1 and SI2 are in general not eye-clean, the impurities may be light in color or scattered and so in up to 20% of cases, SI1 graded diamonds may appear to be eye-clean. That number falls to just 5% for SI2s.
There are many different types of impurities, but feathers and crystals are the most common forms of inclusions found in diamonds.
More On Clarity Grades
The Gemological Institute of America grades diamond clarity on an 11 point scale ranging from Flawless and Internally Flawless (FL/IF) to Included(I1, I2, I3). These categories are founded upon the ability to see the inclusions under 10x magnification. FL/IF to VS2 categories are referred to by diamond experts as "eye-clean" and are the categories of the highest clarity. Diamonds classified as "eye-clean" are considered to have no imperfections visible to the naked eye.
Flawless Or Internally Flawless: FL or IF
Flawless and Internally Flawless certified diamonds are extremely rare. The difference between the two is that internally flawless diamonds (IF), like the FL, are 100% flawless from the inside but IF diamonds will contain surface graining on the outside. These are not technically considered a flaw, but consist in the only point of differentiation between the extremely rare Flawless and the very rare IF clarity grades. FL or IF diamonds may also be referred to as 'LC,' meaning "Loupe Clean".
Very Very Slightly Included 1: VVS1
A diamond of this clarity grade would have one tiny inclusion that can only be located using a powerful microscope. This clarity grade guarantees that the inclusion is invisible even under a 10x magnification loupe. This clarity grade is almost as rare as the IF clarity and as such is highly regarded although not quite as expensive.
Very Very Slightly Included 2: VVS2
These diamonds would only have two tiny inclusions and consistent with the VVS1 grading only a microscope would identify inclusions. However, expert graders may be able to locate a VVS2 inclusion using a 10x magnification loupe but VVS2 still offer a very high level of clarity and are less expensive price than a VVS1.
Very Slightly Included 1: VS1
VS1 diamonds have one small or a few very tiny inclusions that are not visible to the unaided eye (eye-clean) and can only be located, often with difficulty, using a 10x magnification loupe. VS1 clarity diamonds are an excellent choice as they are still eye-clean whilst being less expensive than the VVS categories.
Very Slightly Included 2: VS2
Usually VS2 diamonds have a series of tiny inclusions that like the VS1 grade can only be located using a 10x magnification loupe. VS2 clarity diamonds are an extremely popular as it is the last grade which virtually guarantees an eye-clean diamond. In 95% of cases VS2 diamonds are eye-clean. Rare exceptions, may include VS2 diamonds on EGL or IGI certificates (extremely rare on IGI) and in certain cases, Emerald and Asscher cut diamonds, which may not always be eye-clean, even on GIA certificates. The type of inclusions here would generally be two small inclusions or a series of tiny ones.
Slightly Included 1: SI1
SI1 graded diamonds have two medium or many small inclusions that will almost always be visible to the unaided eye and are easy to locate usinga 10x magnification loupe. Depending on how well placed and lightly colored the inclusions are the stones can appear almost eye-clean and therefore SI1 clarity diamonds can offer exceptional value for those wishing to maximise their budget. An SI1 diamond on a GIA, HRD or AGS certificate will in over 50% of cases be eye-clean depending on the chosen shape. However, as with the VVS2, this grade of diamonds probably won't be eye-clean on Emerald and Asscher cuts, on any certificate.
Slightly Included 2: SI2
SI2 diamonds have a greater number of inclusions that will almost always be visible to the unaided eye. As with the SI1 clarity diamonds, they can offer great value for money and depending on the inclusions it can be possible to find an eye-clean stone at a fraction of the price of higher clarity grades.
I1 Or Lower
These diamonds will always have inclusions clearly visible to the naked eye, even on the strictest certificates, such as those of the GIA. Even though it is still possible for us to source such diamonds upon request, we would recommend choosing SI2 clarity diamonds or above.
Clarity Enhancement/Fracture Filled Diamonds
Fracture filled' or 'clarity enhanced' diamonds are those whose fractures or cracks have been filled in to restore and enhance their brilliance. The process for fracture filling diamonds was developed in 1982 by Israeli diamond cutter Zvi Yehuda and involves filling surface-reaching cracks with molten glass to improve the diamond's clarity. Yet, it was not until the 1990s that fracture filled diamonds began to appear in the market in abundance.
The glass used has a high refractive index similar to that of diamond, making the fractures less visible. The treatment is performed under heat and pressure, sufficient to force the liquid glass into the fractures. This method tends to improve a diamond's clarity by one grade but it doesn't affect the color or weight of the gem. Only diamonds with small cracks can be fracture filled. However, it is important to note that many diamonds contain minute internal "cracks", sometimes described as "feathers" by the retailer, that do not pose a threat to the integrity or life span of the diamond.
The process of fracture filling divides opinion among jewelleers, with many attesting to their advantages and disadvantages. Yehuda originally said that the advantage to fracture filled diamonds is their lower cost, creating the potential for someone to purchase a larger, cleaner diamond than they otherwise would have been able to afford. However, purchasing a fracture filled diamond doesn't guarantee adiscount as they will be paying the same price for the grading of the stone before the fracture was filled. The only difference being that a visible inclusion has now been made "invisible" to the naked eye. Furthermore, fracture filled stones are often too small or too low quality and are therefore rarely submitted to gemological laboratories. Laboratories will not provide a clarity grade as the enhancement is not a permanent treatment and the stone's appearance can diminish over time. Subsequently, it is difficult for the buyer to know exactly what they are buying or if the price is right.
Fortunately it is easy to spot a fracture-filled diamond; simply shake the stone from side to side under a microscope and you will notice a 'flash effect', a play of bright color spanning from a purple to an orangey-yellow. If a diamond has been tampered with the color of the glass can also be a giveaway as a yellow-brownish shade is often made visible in transmitted light, even impacting upon the overall color of the stone.
Diamond Inclusions & Blemishes
Inclusions and blemishes are structural imperfections which affect the clarity grading of diamonds. Inclusions are largely crystals of diamond or a foreign material that has formed within the stone affecting the internal composition, while blemishes are flaws which affect the stone's surface. The size, number, color, location, orientation, and visibility of inclusions and blemishes are all taken into account when evaluating the clarity of a diamond.
Crystals or Mineral Inclusions: Diamonds regularly have miniscule crystals or minerals imbedded within them and these can even be other tiny diamonds. Otherwise, any included and undigested gemstones are more often than not fragments of garnet, diopside, spinel, calcite, olivine, silica or iron oxide. Although the majority of these cannot be viewed prior to magnification, a significantly sized cluster or mass of crystals does detract from a diamond's appearance, lowering its clarity grade and value.
Feathers: These are cracks within the stone that resemble feathers. The durability of a diamond is usually only affected if feathers reach the surface of the stone, which is more susceptible to damage. Small feathers under the surface do not normally create problems. Cleavage planes or internal stress fractures can look like feathers, although these are more commonly found, surrounding included-crystals.
Indented Natural: An indented natural is one which dips below the polished diamond's surface. If a diamond has an indented natural, it would not receive an IF clarity grade because the indented natural counts as an inclusion.
Knots: Refers to a crystal inclusion that appears on the surface of the diamond as a knot. Diamonds with a knot inclusion are usually awarded a lower clarity grade as the flaw is visible to the naked eye (but not always).
Needles: These are long thin needle-shaped inclusions inside a diamond. They appear as a streak of light inside the stone and can sometimes appear in clusters, affecting the overall clarity and value.
Pinpoints: Pinpoints are tiny light or dark crystals present within a diamond that appear either by themselves or in clusters.
Pinpoint Clouds: More significant clusters of tiny pinpoints are referred to as pinpoint clouds due to the white haze they create. Clouds are defined as a dense grouping of tiny pinpoints, consisting of microscopically small dust-like voids or impurities. The clusters create a cloudy zone which even at 10x magnification may not resolve as individual pinpoints, thus affecting the clarity.
Twinning Wisps: These particular defects form as a result of the crystal entwining into a trail during the original stone's growth. This can also be accompanied by graining and strain.