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Jul 14

Jewelry and Gems Buying Guide – Diamonds

Clarifying clarity: How flaws affect diamonds?

Flaws classification, the clarity grade, is one of the most important criteria used to determine the value of a diamond. As with all things in nature, however, there is really no such thing as “flawless.” Even though some very rare diamonds are classified “flawless,” the term is somewhat misleading and you must be sure you understand what it really means.
When we talk about a diamond’s clarity or flaw grade, we are referring to presence of tiny, usually microscopic, imperfections. As it forms in the nature, every diamond develops imperfections. They might be microscopic cracks shaped like feathers, or microscopic diamond crystals, or even crystals of some other gemstone! Each diamond’s internal picture, its internal character, is unique. No two are alike, so the clarity picture can be an important factor in identifying a specific diamond. To the buyer, however, the clarity grade is important because it indicates, on a relative basis, how “clean” the diamond is. The cleaner the stone, the rarer and costlier.

How is the clarity grade determined?

Diamonds used in jewelry are usually very clean, and little, if anything, can be seen without magnification. This has started to change as an increasing number of diamonds with visible cracks or other inclusions enter the market, stones in the I1 – I3 range, and below but for most part, differences in clarity can not normally be seen simply by looking at the stone with the naked eye. The clarity grade is based on what can be seen when the diamond is examined using 10X magnification, as provided by a loupe. The “flawless” grade is given to a stone in which no imperfections can be seen internally (“inclusions”) or externally (“blemishes”) when it is examined with 10X, although at higher power inclusions will be visible in a flawless diamond. For clarity grading purposes, if an inclusion can’t be seen at 10X, it doesn’t exist.
Clarity grading requires extensive training and practice, and proper grading can only be done by an experienced jeweler, dealer, or gemologist. If you want to examine a diamond with the loupe, remember that only in the lowest grades will an inexperienced person be able to see inclusions easily, and even with the loupe it will be difficult to see what a professional will see easily; few amateurs will see anything at all in diamonds with the highest clarity grades.

Types of diamond imperfections

Among the two categories of flaws, internal flaws, or inclusions, and external flaws, or blemishes, are a variety of different types. The following lists will describe them and provide a working vocabulary of diamond imperfections.

Internal Flaws or Inclusions

Pinpoint. Pinpoint a small, usually whitish dot (although it can be dark) that is difficult to see. A group of pinpoints is simply a cluster of pinpoint flaws, and cannot be classified as VVS. A cloud of pinpoints is hazy and is not easily seen.

Dark Spot. Dart Spot may be a small crystal inclusion or a thin, flat inclusion that reflects light like a mirror. It may also appear as silvery, metallic reflector.

Colorless Crystal. Colorless Crystal is often a small crystal of diamond, although it may be another mineral. Sometimes it is very small, sometimes large enough to substantially lower the flaw grade to SI2 or even I1. A small group of colorless crystals lowers the grade from possible VS2 to I3.

Cleavage. A small cleavage is a creak that has a flat plane, which if struck, could cause the diamond to split.

Feather. Feather is another name for a crack. A feather is not dangerous if it is small and does not break out through a facet. Thermoshock or ultrasonic cleaners can make it larger.

Bearding or girdle fringes. Bearding or girdle fringes are usually the result of hastiness on the part of the cutter while rounding out the diamond. The girdle portion becomes overheated and develops cracks that resemble small whiskers going into the diamond from the girdle edge.

Sometimes the bearding amounts to minimal “peach fuzz” and can be removed with slight re-polishing. Sometimes the bearding must be removed by faceting the girdle. Bearding that is quite minimal can be classified as IF.

Growth lines of graining. Growth lines of graining can be seen only when examining the diamond while slowly rotating it. They appear and disappear, usually instantaneously. They appear in a group of two, three, or four pale brown lines. If they can not be seen from the crown side of the diamond and are small, they not affect the grade adversely.
Knaat or twin lines. These are sometimes classified as external flaws because they appear on the surface as very small ridges, often having some type of geometrical outline, or as a small, slightly raised dot with a tail resembling a comet. These are difficult to see.

External Flaws or Blemishes

A natural. A natural usually occurs on the girdle and looks like a rough, unpolished area. It may resemble scratch lines or small triangles called trigons. A natural is a remnant of the original skin of the diamond, and is often left on the girdle when the cutter tries to cut the largest possible diameter from the rough. If a natural is no wider that the normal width of the girdle and does not disrupt the circumference of the stone, some do not consider it a flaw.

Often naturals are polished and resemble an extra facet, especially if they occur below the girdle edge.

Nick. Nick is a small chip, usually on the girdle, and can be caused by wear, especially if the girdle has been cut thin. Sometimes a nick or chip can be seen on the edge of the facets where they meet. If small, this bruised corner can be polished, creating an extra facet. This usually occurs on the crown.

Girdle roughness. This blemish appears as crisscrossed lines, brighter and duller finishing, and minute chipping. This can be remedied by faceting or re-polishing.

Pits or cavities. Pits or cavities holes on the table facet, especially if they are deep, will quickly lower the grade of the stone. Removing pits involves re-cutting the whole top of the stone, and can also shrink the stone diameter.

Scratch. A scratch is usually a minor defect that can be removed with simple polishing. remember, however, that in order to re-polish the stone, it must be removed from its setting, and then reset after it has been polished.

Three commonly used clarity grading systems

The following three systems are commonly used for grading diamond clarity:

Gemological Institute of America, or GIA

American Gem Society, or AGS

Hoge Raad Voor Daimant, The Diamond High Council Of Belgium, HRD

The major grading system used in the United States, like color grading system, was developed by the GIA as part of its diamond grading system. The GIA system is only one of several in use, but it has gained wide acceptance in the United States and many other counties around world.

Basically these systems grade the stone for its imperfections, both its internal inclusions and external blemishes. The clarity grade represents the total picture, the type, number, placement, and color, of the diamond’s imperfections. These can be white, black, colorless, or even red or green in rare instances. The “flaw” grade is more commonly referred to as the “clarity” grade today.

There are eleven grades on the GIA scale, beginning with FL, Flawless, colorless, well cut stone, particularly from one carat and up, is extremely rare and is prices proportionately much higher than any other grade. Some jewelers insist such stone do not exist today.

The grade IF is given to a stone with no internal flaws and with only minor external blemishes, small nicks, pits, or girdle roughness, not on the table, that could be removed with polishing. These stones, in colorless, well proportioned makes, are also rare and priced proportionately much higher than other grades.

VVS1 and VVS2 are grades given to stones with internal flaws that are very, very difficult for a qualified observer to see. These are also difficult grades to obtain, and are priced at a premium.

VS1 and VS2 are grades given to stones with very small inclusions difficult for a qualified observer to see. These stones are more readily available in good color and cut, and their flaws will not be visible except under magnification. These are excellent stones to purchase.

SI1 and SI2 grades are given to stones with flaws that a qualified observer will see fairly easily with 10X magnification. They are less rare than other grades, so they sell at a lower price. They are still highly desirable and are being used increasingly in very fine jewelry, especially in sizes over two carats with good color and cut.

The imperfect grades are given to given to stones in which flaws may be seen by a qualified observer without magnification; they are readily available and are much less expensive. They are graded I1, I2, and I3. These grades are called first pique (pronounced pee-kay), second pique, and third pique in some classification systems. I1, I2, and some I3 grades may still be desirable if they are brilliant and lively, and if there are no inclusions that might make them more susceptible than normal to breaking, and so should not be eliminated by a prospective purchaser who desires lovely diamond jewelry. As a genral rule, however, imperfect grades may be difficult to resell should ever try to do so.

Exercise care when considering a low clarity grade

For those considering a diamond with an I3 clarity grade, we must issue a word of warning: some diamonds graded “I3” are actually industrial quality and not suited for jewelry use. Some cutters are cutting material that is lower than what is considered acceptable for jewelry. Since there is no grade lower than I3, these stones are lumped in with other “better” (jewelry quality) I3 stones, and are given an I3 grade as well. But, I3 grade diamonds are not all comparable in terms of their clarity, and some should sell for much less than others. Be sure to shop around and compare “I3” diamonds to become familiar with what is acceptable for jewelry use.

To what extent does clarity affect the beauty of a diamond?

The Clarity can dramatically affect the value of a diamond because of differences in rarity, but it is very important to understand that clarity may have little or no effect on the beauty of a diamond if it falls within the first eight grades (FL – SI). Few people can discern any difference between stones until they reach the imperfect grades, and even then some have difficulty seeing anything in the stone without magnification. Juggling the clarity grade can give you tremendous flexibility in getting a whiter or larger diamond for your money, but also means you must take care to know for sure what the specific clarity grade is.

Clarity Enhancement

Today technological advances have made it possible to improve diamond clarity. Several clarity enhancement techniques are available, some more or less permanent, and others definitely not permanent. Unfortunately, clarity enhancement frequently is not disclosed, either to jewelers themselves or by jewelers to their customers. It is important to buy diamonds from knowledgeable, reputable jewelers who check for such treatments. In addition, prior to buying any diamond you must ask whether or not the stone has been clarity enhanced. If te stone has been enhanced, ask what method was used, and be sure this is stated on the bill of sale. In addition, be sure to ask about special care requirements that might be necessitated by the process.

The two most widely used methods of clarity enhancement are laser and fracture filling.

Laser.

Laser treatment is used to make flaws less visible, and thus improve the stone aesthetically. Using laser technology, it is possible to “vaporize” black inclusions so they practically disappear. With the loupe, however, an experienced jeweler or gemologist can see the “path” cut into the diamond by the laser beam. This path looks like a fine, white thread starting at the surface of the stone and traveling into it. The effects of the laser treatment are permanent. If a lasered diamond is accompanied by a GIA diamond grading report, the report will state that the stone is lasered.

A lasered stone should cost less than another with the same clarity, so it may be an attractive choice for a piece of jewelry, as long as you it’s lasered and therefore pay a fair price for it.

Fracture filling.

Fractures, cracks or breaks, that would normally be visible to the naked eye and detract from the beauty of a diamond can often be filled with a nearly colorless, glass like substance. After filling, these breaks virtually disappear and will no longer be seen, except under magnification. Filling is not a permanent treatment, and special precautions are required when cleaning and repairing jewelry containing a filled diamond. With proper care, such stones may remain beautiful for many years. Careless handling, however, can cause the filler to leave the stone or change color, resulting in a much less attractive diamond. Some filling materials are much more stable than others, but at present it is usually not possible to know what filler has been used in a given stone. Should the filler be accidentally removed, your jeweler can have the treatment repeated to restore the stone’s original appearance. GIA will not issue a grading report on a filled diamond.

Filled diamonds cost much less than other diamonds. They can be very affordable alternative as long as you know what you are buying, understand the limitations, and pay the right price.

How does the position of a flaw affect a diamond’s grading value?

As a general rule, the position of any given inclusion will progressively downgrade and devalue a diamond as indicated below:

If seen only from the pavilion side, or clearly only from the pavilion side, a flaw has the least adverse effect, since it is the least visible form the top.

If positioned near the girdle, while perhaps more visible than described above, a flaw is still difficult to see, and hardly noticeable from the top. Such flaws can be easily covered with the prong of a setting.
Under any crown facet (other than a star facet), a flaw is more easily visible, except when near the girdle.

Under a star facet, a flaw will be much more easily visible.
Under the table is the lest desirable position, as it places the flaw where it is most noticeable, and may have the greatest effect on brilliance or fire, depending on the stone’s size or color.
Sometimes a small black or white flaw may be in such a position that it is reflected within the stone. It may be seen as a reflection to the opposite side of the stone, or, more unfortunately, it may reflect itself as as eight times around the bottom or near the culet or the stone. A diamond with such a flaw might otherwise be classified as a VS1 or VS2, but because of the eight-fold reflection resulting from its unfortunate position, the flaw grade will be lowered.

Remember, a diamond does not have to be flawless to be very fine stone and to have a high value. Personally, we prefer a stone that might be slightly imperfect but has fine color and brilliance over a flawless stone with less sparkle and a less fine color. Color and brilliance are considered the most important factors in terms of a stone’s desirability. And remember: Even a diamond graded I3 can be beautiful and brilliant.

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