CRYSTAL CLEAR
When we speak of a diamond's clarity, we are referring to the presence of identifying characteristics on and within the stone. While most of these characteristics are inherent qualities of the rough diamond and have been present since the earliest stages of the crystal's growth below ground, a few are actually a result of the harsh stress that a diamond undergoes during the cutting process itself.
HOW DIAMOND CLARITY GRADED
All diamonds are graded based on their appearance--that is, the presence or absence of blemishes and inclusions--under 10x magnification. They are graded on a scale that ranges from Flawless to Imperfect:
Flawless diamonds have no blemishes or inclusions. To be graded as Flawless, the diamond must appear completely clean to the gemologist under both a jeweler's loupe and a microscope at 10x magnification.
Internally Flawless (IF) diamonds have no internal inclusions and only very, very minor blemishes that are apparent only under 10x magnification.
b>Very Very Slightly Included (VVS) diamonds are graded within one of two subcategories: VVS1 and VVS2. In both categories, the inclusions which are present are extremely hard to see, even for a trained gemologist. Often, even under magnification the inclusions are still only visible from the pavilion (upside-down position) and not in the face-up position. The most typical inclusions found in diamonds within these two clarity grades are a few tiny pinpoints, faint clouds, tiny feathers, or internal graining.
Very Slightly Included (VS) diamonds are also graded within one of two subcategories: VS1 and VS2. They have minor inclusions which are minute and impossible to detect with the naked eye, but which are apparent to a gemologist under 10x magnification. Inclusions which are typical in these clarity grades include small included crystals, feathers, distinct clouds, and groupings of pinpoints.
Slightly Included (SI) diamonds fall within one of two subcategories: SI1 and SI2. Within both of these categories, inclusions are often centrally located and easily detectable under 10x magnification. In some cases, an inclusion may even be visible to the naked eye when the diamond is held a couple of inches away from the viewer's eye, though no inclusions will be visible when the diamond is mounted or held at normal wearing distance (12" to 16") from the eye. Typical inclusions in these clarity grades are included crystals, clouds, and feathers.
Imperfect (I) diamonds actually are subdivided into three categories--I1, I2, and I3--though it is unlikely that you will ever see an I3 being sold as jewelry (because of the severity of their inclusions, they are usually used as industrial abrasives instead). However, it is not uncommon to find many attractive I1 and I2 diamonds being sold today. These grades contain inclusions that are very obvious under 10x magnification; these inclusions may even be visible to the naked eye as well. Typical characteristics of these grades include large included crystals and feathers. Because of their lower clarity, I1 and I2 diamonds can offer an excellent cost savings for customers who are working with a smaller budget but still desire a good size diamond.
PERFECTLY CLEAR
Clarity characteristics are usually divided into two categories:
BLEMISHES - Just like the blemishes we notice on our own faces every now and again, these occur on the surface of a diamond and are usually a result of the environment that the diamond has encountered, rather than an inherent quality of the diamond crystal. The most common types of blemishes found on diamonds are:
- Extra Facets. These are usually cut to remove a near-surface inclusion and to raise the overall clarity grade of the polished diamond. In many cases, they do not affect the clarity grade. In most cases, they are undetectable to the naked eye.
- Naturals. A natural is a small part of the original rough diamond's surface which is left on the polished diamond, frequently on or near the girdle. While these are blemishes, they might also be regarded as a sign of skilled cutting; the presence of a natural reflects the cutter's ability to design a beautiful polished gem, while still retaining as much of the original crystal's weight as possible. In many cases, naturals do not affect the clarity grade. In most cases, they are undetectable to the naked eye. Another type of natural is the Indented Natural; in this case, the portion of the original rough diamond's surface which is left on the polished diamond dips slightly inward, creating an indentation. Usually, the cutter makes an effort to cut the polished diamond so that the indented natural will confined to either the girdle or the pavilion (making it undetectable to the naked eye in the face-up position).
- Surface Graining. This is one of the few types of blemishes which actually occur during a diamond's growth rather than during the cutting process. Despite its name, surface graining does not exactly occur on the diamond's surface; it is an integral part of the crystal's structure and usually cannot be removed from the diamond without causing significant weight loss. Graining is caused by minor irregularities and stresses which occurred millions and millions of years ago when the diamond crystal was still growing. Under a microscope, this graining appears as transparent wavy lines running over the diamond's surface; without a microscope these lines cannot be seen at all.
- Included Crystals. These are exactly what they sound like: minute crystals of other minerals--and, in some cases, even other small diamonds--that were absorbed by the diamond crystal as it was still growing. Some are transparent and some have color, depending on what type of crystals they are. Under a microscope they often look like little round bubbles inside the diamond, but some can have more unusual shapes. In the majority of circumstances, included crystals are undetectable to the naked eye. When setting the clarity grade of a diamond, gemologists consider not only the mere presence of included crystals, but also the number of crystals present, their size, and their nature (i.e. transparent or dark; large or small).
- Pinpoints. These are included crystals that are so tiny that, even when magnified to 10x, they still only look like little dots. Even for trained gemologists, these can sometimes be tough to find. Except when gemologists are trying to distinguish between the highest clarity grades (Flawless, Internally Flawless, and Very Very Slightly Included) these types of inclusions rarely impact a diamond's clarity grade significantly.
- Needles. Needles are yet another type of included crystal. Under magnification, instead of appearing as little bubbles, they look like tiny super-slender needles, as their name implies.
- Knots. A knot is an included diamond crystal that reaches from the inside to the surface of the polished diamond.
- Chips. A chip is a small, very shallow opening on a diamond's surface, usually on or near the girdle. It may be a naturally occurring opening in the diamond, or it may be created, either by the removal of a tiny included crystal or by a sharp impact with another object.
- Cavities. A cavity is a larger version of a chip. Cavities are sometimes created by the diamond cutter when an included crystal near the surface of the rough diamond is removed during the faceting process, leaving an indentation where the crystal was originally imbedded.
- Feathers. These are small fractures in a diamond. They are usually caused by the tremendous stress that the diamond suffered while it was growing underground. In some cases the feather both begins and ends within the diamond's surface and, in other cases, the feather begins inside the diamond and extends to the surface. Likewise, when viewed under magnification, some feathers are transparent and others have a light white appearance to them. The term "feather" comes from the fact that, under magnification, these fractures often seem to have an indistinct, feathery shape to them. The size, number and quality of these feathers are usually a significant determining factor in setting the clarity grade of a diamond. However, while the idea of buying a diamond with "fractures" may sound scary, the reality is really much better than it sounds at first; with normal wear and care, it is exceptionally unlikely that such diamonds will ever "crack in half" as many customers fear. Consider this: even with the fractures, these diamonds survived their growth and their journey to the surface intact. Once on the surface, they also survived the mining process, as well as the brutal stresses of the diamond cutting process. Though diamonds are certainly not invulnerable to damage, basic consideration to their care and handling during everyday wear will most likely protect them over the course of several human lifetimes. If you are still concerned about keeping your diamond safe from damage, it would be wise to select a jewelry setting that protects it well. Bezel settings (which cover the diamond around its entire edge) and prong settings that carefully cover any vulnerable areas, such as the corners or points of fancy shapes, are two excellent choices.
- Internal Graining. Like surface graining, which is described above under the category of 'blemishes,' this is a naturally occurring phenomenon in some diamonds. The appearance of internal graining is very similar to that of surface graining, except that it occurs within a diamond rather than on the diamond's surface.
- Clouds. You'll notice from many of the above descriptive terms that gemologists have a bit of a poetic nature; 'needles,' 'feathers,' 'clouds'--these are just a few examples of the vocabulary of the gemologist. While the terms are poetic, they are also an effective way to describe the appearance of many inclusions that would otherwise be difficult to explain. Clouds are actually a grouping of a number of extremely tiny inclusions that are too small to be distinguishable from one another, even under magnification. The result is that, under a microscope, this grouping often looks like a soft transparent cloud inside the diamond. Of course, clouds cannot be seen with the naked eye. Usually, this sort of inclusion does not significantly impact a diamond's clarity grade.
In some cases, cutters may choose to use certain treatments in order to improve the clarity grade of a diamond. Some of these treatments are common and accepted practices; others are less permanent and less accepted.
Laser Drill Holes: Laser drill holes are one of the few man-made inclusions that can occur inside a diamond. Why on earth would anyone want to drill holes into a perfectly good diamond? It may seem counter-intuitive, but drilling this type of hole into a diamond can actually raise its clarity grade. In some diamonds, the clarity grade may be determined mainly by the presence of just one or two dark included crystals in a diamond that is otherwise relatively free of inclusions. In certain circumstances, the diamond cutter will decide to use a procedure to remove the dark inclusions and, hopefully, increase the clarity of the diamond. How is it done? First of all, a hole is precisely made with state-of-the-art equipment; it extends no further than it needs to, and its width is so small (about the size of a pinpoint) that a loupe or microscope is usually required to detect it. Next, a strong acid solution is forced into the new hole. Since diamonds are resistant to acids, the solution actually dissolves the included crystal while leaving the diamond completely unharmed. The end result is a more transparent. The structural stability of the diamond is not compromised in any way by this hole, and the process is permanent.
Fracture Filling: Fracture filling is a process that is performed on certain diamonds which have white feathers that reach to the surface of the stone. To reduce the appearance of the feather, thereby making the clarity seem higher, some cutters or jewelers will force a liquid into t0he diamond through this fracture. The liquid then hardens to a clear solid, filling the fracture and reducing its appearance under magnification. However, this treatment is not permanent; under sufficiently high heat, the liquid may melt and leak out of the diamond, leaving the diamond in its original state. Because this particular type of treatment is not permanent, and because many in the diamond trade regard it as a somewhat deceptive practice, most labs (including GIA and AGS) refuse to grade diamonds that have been fracture filled.
WHAT DOES IT ALL MEAN?
Grading is done in a lab by experts using sophisticated gemological equipment. When a gemologist grades a diamond, he or she also creates a "plot" of a stone--essentially a blue print of every clarity characteristic that appears in the diamond. This plot is found on the right-hand side of the diamond grading certificate. (An exception is the case of some smaller weight diamonds which are certified with GIA 'dossiers' rather than with full-size grading reports; dossiers describe the main characteristics of the diamond but do not plot them out. Every diamond that is accompanied by a dossier also has the certificate number microscopically laser-inscribed on its girdle as proof of its identity.) While the presence of these clarity characteristics do lower the clarity grade, and therefore the value, of a diamond they can also be viewed as proof of a diamond's identity. Since no two diamonds are exactly the same, comparing the uniqueness of your diamond's clarity characteristics with the plot provided on the diamond certificate offers assurance that the diamond you pay for is the same diamond you receive.
