Diamond Clarity Ratings

While buying diamonds, most people base their decision on size and sparkle. However, similar stones with a large disparity in price leave us flummoxed. To understand this, we need to look at the grades. The value of this gemstone is estimated according to the four Cs: clarity, color, carat, and cut. Richard T. Liddicoat of the GIA (Gemological Institute of America) proposed and developed the GIA Clarity Grading System in 1952. Over time, several changes have been incorporated into the system. Most of them are graded according to the GIA chart, which considers minute differences while categorizing these stones. Among the different qualities the chart is graded on, clarity, color, and cut are qualitative values, whereas carat, which is the weight of the diamond, is a quantitative value.

To the uninitiated, diamond clarity would mean how clear that stone is to look at. However, its explanation goes much deeper than that. There are several minute formations within this stone called inclusions, which are often not visible to the naked eye. These inclusions, along with surface defects called blemishes, reduce its value. Inclusions are the outcome of events that took place while this stone was forming. They might be in the form of crystals of a foreign material, or another diamond crystal, or structural imperfections such as tiny cracks. Slight inclusions usually do not affect its sparkle. It is only when these "clouds" are large, that they can affect its ability to transmit and scatter light. As is obvious, the higher its clarity grade, the more expensive it is. Those considered "flawless" are incredibly rare.

There are several types of inclusions and blemishes, which affect the clarity ratings. Inclusions may be in the form of clouds, bearding, feathers, cleavage, included crystals or minerals, cavities, knots, and internal graining. Blemishes include pits, polish lines, nicks, grain boundaries, scratches, naturals, and chips. New characteristics that may appear on this gemstone as a result of enhancement procedures, such as laser lines, are also considered inclusions/blemishes.

The following table is the currently used GIA diamond clarity scale. The six categories and their eleven grades are:

1. The rarest and most expensive ones fall into the Flawless category (FL). They have no inclusions or blemishes visible under 10x magnification.
2. The next category on this chart is Internally Flawless (IF), which constitutes those that have no inclusions visible under 10x magnification. Diamonds with small surface blemishes also fall into this category.
3. Those that have minute inclusions, which even skilled graders struggle to detect under 10x magnification, are awarded the grade of VVS or Very, Very Slightly Included. This category is further divided into VVS1 and VVS2.
4. Those included in the Very Slightly Included category (VS) have minor inclusions that could be between difficult to somewhat easy for a trained grader to spot, when examined under 10x magnification. This category is also divided into two grades: VS1 is a superior grade to VS2. In a majority of VS diamonds, inclusions are only visible under magnification. In rare cases, some VS2 inclusions are visible to the naked eye.
5. The Slightly Included (SI) grade is given to those that have noticeable inclusions. These inclusions can easily be identified by a trained grader, when viewed under 10x magnification. The SI category is subdivided into two grades: SI1 and SI2. These inclusions are sometimes noticeable to the naked eye.
6. The last category is the Included category (I). These diamonds have obvious inclusions that are clearly visible to a trained grader under 10x magnification. Usually, the inclusions are also visible to the human eye, and can decrease the durability of the stone. This category is divided into three grades: I1, I2, and I3. Large inclusions affect its sparkle.

Minor inclusions or blemishes are also considered the fingerprint of this stone, as they are used as unique identifying marks. While minor inclusions are not a cause for concern, large cracks can diminish its resistance to fracture. Before buying one, be sure to seek advice on these ratings. Once you are aware, you will be in a position to judge the clarity of diamond rings, earrings, pendants or any other form of such jewelry you wish to buy.