Diamond Clarity
Of all the diamonds that are mined each year only about 25% becomes jewelry. The rest go to industrial uses. That means that 75% of all diamonds do not have a high enough quality for jewelry. Of the 25% that does become jewelry, most are lower grade and much is "promotional" grade.
As a diamond forms over millions of years (about 75 - 120 miles below the earth's surface), various factors often cause the diamond to form a number of irregularities within the diamond. These are the diamonds "birthmarks" and are referred to as inclusions. These inclusions, which are important in fingerprinting the unique characteristics of a diamond, (no two diamonds have exactly the same clarity characteristics) also help distinguish it from a diamond "simulant."
These inclusions can take many forms, from tiny pinpoint crystallization, to "feathers" (small or large fractures or cleavages within the stone), to "clouds," to large or small cavities, to "included crystals" (a solid mineral crystallization within the diamond - these can occasionally even be other minerals such as peridot, rubies or garnets).
Another type of clarity characteristic is called a blemish. Generally, blemishes are characteristics on the diamond's surface and are often caused by the diamond cutting process itself, or by handling, or even day to day wear. These blemishes include abrasions (tiny nicks or rough spots), extra facets, nicks, pits, scratches and polishing marks.
There are five factors which impact the clarity of a diamond. These are:
- Size: Generally, the larger the inclusion, the easier the inclusion is seen, and the lower the clarity grade. Large inclusions can also affect the stone's durability.
- Number: Although a greater number of inclusions/blemishes can lower the grade, clarity grades are usually determined by how easily they are seen. Several minute pinpoints may lead to a VVS grade whereas a single large, dark inclusion may lead to an I grade. Having noted this, a greater number of inclusions/blemishes tend to lower the grade.
- Position: The most obvious place for an inclusion is directly under the table. Inclusions under other facets are usually less visible. Some inclusions lie in positions where they are reflected many times (mirror images) through many facets, which greatly impact the clarity grade.
- Nature: This is based on two distinctions: whether the inclusion is internal or external, and whether it poses any risk to the stone. Below the grade of Internally Flawless (IF), blemishes generally have little effect on the stone's clarity grade. Inclusions, which are detrimental to the durability of the stone (large feathers [fractures] running to the surface of the stone, can run a risk of breaking the stone).
- Color and Relief: Dark colored inclusions are easier to see than light colored or colorless inclusions. Relief refers to the contrast between the inclusion and the stone. The greater this difference the lower this factor will impact the clarity grade.
The Gemological Institute of America (GIA) has developed a clarity grading scale divided into eleven different grades. Generally these grades are determined by how visible inclusions and/or blemishes are visible at 10X magnification. A jeweler's loupe provides this 10X magnification but from my experience, most unskilled consumers have a difficult time accurately identifying clarity characteristics (some of which are rather large) with these hand-held loupes. GIA Gem Trade Laboratories use 10X binocular vision microscopes to accurately identify clarity characteristics and determine diamond grades. So do we. As a consumer, you shouldn't settle for less. If you, as an unskilled diamond viewer, cannot see an inclusion in a Jewelers loupe that doesn't mean that large or noticeable inclusions aren't visible. You should always demand to see your prospective diamond purchase under a binocular vision microscope.
The GIA clarity grades are as follows:
Flawless (FL) : No inclusions or blemishes visible to a skilled grader under 10X magnification.
Internally Flawless (IF) : No inclusions and only slight blemishes visible to a skilled grader under 10X magnification.
Very Very Slightly Included (VVS1 and VVS2) : Minute inclusions, which are difficult to see even by a skilled grader under 10X magnification. For VVS1 these inclusions are extremely difficult to see, and only visible from the pavilion (bottom), or shallow enough to be removed by minor re polishing. For VVS2 these inclusions are very difficult to see.
Very Slightly Included (VS1 and VS2) : Minor inclusions, which are difficult (VS1) to somewhat easy (VS2) to see by a skilled grader under 10X magnification.
Slightly Included (SI1 and SI2) : Noticeable inclusions, which are easy (SI1) to very easy (SI2) to see by a skilled grader under 10X magnification. Grade-setting inclusions are normally centrally located and noticed immediately under 10X magnification. A diamond with an eye-visible inclusion may still be graded SI dependant on the other components of five clarity impact factors.
Included (I1, I2, and I3) : Obvious inclusions and often-visible face-up to the naked eye. I3 inclusions may threaten durability of stone. It has been my experience that many people, because they have little or no experience in viewing diamonds, sometimes have a difficult time seeing I1 inclusions with the naked eye - and even sometimes with a hand-held loupe. If a consumer is unable to see an inclusion with a loupe, then they are at the mercy of the sales persons claim (whether that be skilled grading judgment, unskilled opinion, or unethical deception).
