Clarity Grade Definitions (6.50)
Remember that clarity grading is not an exact science and remains somewhat
. Naturally with experience, you will become more comfortable in grading clarity with confidence. Each clarity grade category has a range within itself. The higher the grade, the smaller the range. A VVS1 will have a very narrow range of acceptable inclusion characteristics, in contrast to an SI2 that will have a much wider range of acceptable inclusion characteristics.
Blemishes have very little effect on clarity grading unless the blemishes are substantial enough to take away from the beauty of the stone. Generally they will only make a grade difference in IF, VVS1, and VVS2. Often caused in the cutting process, the cutter will generally let them be, since there’s not much effect on value or salability.
FL Flawless: At this best clarity grade, a stone will not show any type of inclusion or blemish under 10x magnification. Very Rare.
IF Internally Flawless: This clarity grade will not have any type of inclusions, but may show some type of small blemish under 10x magnification, keeping it out of the FL category.
VVS1 Very Very Slightly Imperfect (higher level): At this clarity grade, it will be very, very difficult to detect inclusions of any type. Typically these would be a single to very few pinpoints, seen under 10x magnification.
VVS2 Very Very Slightly Imperfect (lower level): At this clarity grade, it will still be very difficult to detect inclusions of any type. Slightly lower than VVS1, it will still be a very clean stone with perhaps a few scattered pinpoints. If a crystal could be recognized (by its geometric pattern) in a fairly visible location, chances are that such a stone would be considered lower than a VVS2.
VS1 Very Slightly Imperfect (higher level): For this clarity grade, imperfections should be relatively easy to detect with some scrutiny under 10x magnification. A small detectable well-formed crystal in an easily viewed location would likely be graded a VS1. A small cloud by the girdle might be considered a VS1. A thin feather about 2/3s the length of an upper girdle facet could make the stone a VS1.
VS2 Very Slightly Imperfect (lower level): With a trained eye under 10x, imperfections should be very easy to detect. A small cloud under the table could be graded a VS2. A small feather the length of 1½ stars at the edge of the table could be a VS2. A small black crystal under a bezel facet could be a VS2.
SI1 Slightly Imperfect (higher level): Even with an untrained eye, the inclusions will be quite visible under 10x magnification. An SI1 inclusion could be visible to the naked eye through the pavilion, but if visible through the crown for reasons such as a very large stone or a very large table, very little brilliance/disperion or obvious contrast may be the case. An eye-visible SI1 would be very unlikely however. A medium-sized white crystal near the culet reflecting a few times could be an SI1. An obvious black crystal near the girdle could be graded an SI1. A white feather on the edge of the table spanning the length of two stars with a few tiny feathers off to the side, could also be an SI1.
SI2 Slightly Imperfect (lower level): Even with the untrained eye, the inclusions will be extremely obvious under 10x magnification. Depending on the size, contrast and location of the inclusion in an SI2, it may not always be a 100% eye-clean stone.
SI3 Slightly Imperfect (lowest level): Although GIA does not accept this clarity grade, it is a commonly-used term by dealers. This is where stone value starts to fall noticeably, since demand drops off and availability increases. This grade will obviously be a borderline call between an SI2 and an I1. The stone is not good enough to be called an SI2, but it is not imperfect enough to be an I1. As a result, the SI3 has been adopted by much of the trade, including the Rapaport Diamond Index and many of the gem labs. SI3 will show severely obvious inclusions under 10x magnification, but will probably not have a large dense inclusion that starts to become obvious to the naked eye. Some SI3s may be eye-clean, but once viewed under 10x, you will understand why the stone should not fall in the SI2 category. A diamond with a large number of black and white crystals throughout the whole stone, but not dense enough to be seen with the naked eye, could be an SI3. A large brownish colored feather extending the distance of five upper girdle facets with the width of one facet, could be an SI3. A dense cloud extending from the edge of the table to the girdle across two main facets, could be an SI3. An SI2 which has an inclusion that has partially fallen out, could be downgraded to an SI3 (or I1 depending on its severity).
I1 Imperfect (highest level): Under 10x magnification, these inclusions will be severely obvious. Open cavities are common and problems can often result in everyday wear due to poor durability. Generally an I1 clarity can be determined easily under good light with the naked eye. Sometimes due to the types of inclusions, such as a large amount of scattered crystals, the stone may actually be eye-clean. Generally the inclusions will have some effect on the brilliance and dispersion, due to the interruption of light paths through the stone. Especially watch for fracture filling and laser drilling in this quality of stone.
I2 Imperfect (lower level): Under 10x magnification, the inclusions begin to dominate a significant portion of the diamond. There is still a substantial amount of clearness in the stone, but the light traveling through the diamond is noticeably affected. Open inclusions and large cavities are common, so that poor durability will usually be a factor. Inclusions will always be noticeable to the naked eye, unless the stone contains a very large number of small crystals, giving the diamond a hazy appearance. Even when hazy, technically the inclusions are considered as visible, since they are the cause of the haziness.
I3 Imperfect (lowest level): Under 10x magnification, the inclusions will be extremely obvious. The degree of clearness in the diamond is further diminished in going from I2 to I3. A large part of the light traveling through the stone is affected, naturally giving an almost lifeless appearance to the diamond. Again, open inclusions and cavities are common, making durability an even greater concern than for the I1 to I2 clarities. By the naked eye, the inclusions will be quite obvious, showing very little fire, especially when comparing it to an eye-clean stone. Some dealers use the terms I4, I5, etc., but this is not common. Below the I3 clarity grade, a diamond is so imperfect that the value will not be high enough to be concerned about specific grades or descriptions. The author suggests grading terms such as reject or very imperfect for such cases.
The following photographs have been chosen for the purpose of illustrating average clarity grades. You will often encounter borderline calls and will have to use your best judgment. These illustrations will give you an idea of what precise clarity grading is all about. Only a lot of experience can help you toward the goal of expertness in all diamond aspects, including clarity grading.
Due to photographic limitations, many of these images are shown at higher magnification than the standard 10x.