AGS Diamond Scales
Diamond Color Scale
The numerical AGS diamond color scale starts with 0 translating to a D grade, and increases by 0.5 for each letter increment. For example, an AGS diamond grading of 0.5 is a GIA/EGL grade of E. Thereafter, 1.0 is F and 1.5 is G. The scale ends with 9.5 as W and 10.0 encompassing X, Y, and Z.
Diamond Clarity Scale
The industry standard for diamond clarity grading is based on the GIA’s alphabetical grading scale. The standard GIA clarity grading scale contains six main grades (from highest to lowest): FL, IF, VVS, VS, SI and I. FL (Flawless), diamonds don’t have flaws visible under 10x magnification. IF (Internally Flawless) diamonds have only insignificant surface blemishes. Then comes VVS (Very Very Slightly Included) and VS (Very Slightly Included) diamonds. Finally, there are SI (Slightly Included) and I (Included) diamonds, with the term “inclusion” referring to any diamond flaws. The EGL uses the same scale but includes their unique "SI3" clarity grading, an EGL-exclusive subdivision of the SI clarity range. This new grade caused concern because it added a new clarity grade that departed from the widely accepted GIA clarity scale which divides the SI grade into SI1 and SI2, with I1 as the next lowest grading after SI2. Although seemingly harmless, the new SI3 grade sparked controversy because unassuming customers may be purchasing an EGL SI3 diamond without realizing that it may be equivalent to a GIA I diamond instead of a SI diamond. This one grade difference is significant because SI diamonds may or may not have inclusions visible to the naked eye while I diamonds will usually have flaws that are easily visible, causing a significant price drop between the two categories.Although AGS certifications for clarity use a numerical grading scale, its grades can be easily converted. An AGS 0 is a GIA/EGL Flawless and Internally Flawless, 1 is VVS1, 2 is VVS2, 3 is VS1, 4 is VS2, 5 is SI1, 6 is SI2, 7 is I1, 8 is I1 and I2, 9 is I2 and I3, and 10 is I3.
Diamond Cut Scale
A similar pattern applies to the diamond cut scale. The GIA and EGL use a descriptive diamond cut scale: Ideal, Excellent, Very Good, Good, Fair, and Poor. The AGS numerical scale translates as follows: 0 (Ideal), 1 (Excellent), 2 (Very Good), 3 and 4 (Good), 5, 6, and 7 (Fair), and 8, 9, and 10 (Poor). While the unique numerical diamond grading scale of the AGS may seem unusual at first, it is actually a quite clean and simple way to understand your diamond. When purchasing diamonds, it is wise to research the laboratory behind your diamond certificate and their unique grading system.
Diamond Grading Process
During the grading process, the gems are graded on an electronic colorimeter, which is located at the headquarters of the AGS and is available to its members. A set of what is called; master diamonds are used to measure the quality of the diamonds. The master sets are color-graded diamond sets that are of differing grades and colors and are both owned and maintained by the members of diamond ratings committee. They are graded individually on the colorimeter that is at the headquarters. Their main purpose is to be used as comparison in the grading of the other diamonds.
These master sets are used for ensuring that the diamonds are graded as close to the master set as possible. They consist of a minimum of five stones measuring one-third of a carat, or a larger percentage. If a master set is unavailable, diamonds that have not been found similar to a part of a master set , or which had been graded on the colorimeter; can also be used as a comparison-grading tool, if the color, when seen by the eye, is closer to the color of the stone being compared upon examination. Diamond master sets, which have been graded on the colorimeter, are colorless and look yellow. If the diamond being compared has a green, brown, or yellow-looking body, then it is best to compare and grade it with a master diamond that has a yellow-looking color, but only the depth can be compared.
The grading process involves an ultraviolet-free daylight, or the equivalent and no reflection of color, the diamond that is being graded along with the master. The diamond and the one which is being assessed should be viewed along with the other from the master set, over a full white background. The direction should be perpendicular to that of the pavilion facets, or girdle. Small differences in color is detected by magnification. It also allows small areas to be examined on two stones to ensure that the comparison was done on the body color and not the reflected color.
Color Impact on AGS Grading Process
In order to ensure that you, the consumers get authentic and high quality diamonds, The American Gem Society was formed to oversee the process. The American Gem Society, or AGS as it is commonly known, was founded by a group of leading jewelers in 1934. With a goal of creating an organization that would assist in protecting consumers from less than accurate advertising of diamonds, and of fraud. They have superior skills in determining whether or not a gem is fake, or less than perfect. This has resulted in many unsuspecting consumers being saved from being robbed, because of their lack of knowledge in buying gems.
If you are going to buy an AGS diamond, do not look only at the way it sparkles, you have to request the AGS diamond grading report from the AGS. With this report, you, as the consumer, can then see for yourself, all the factors that contribute to it being a valuable diamond. The standards that are used by the AGS certification board to grade diamonds have made the process a lot easier, as they created standards by which the color, cut, and clarity are judged, on a scale of 0 to 10. The scale begins at 0, which is the highest grade and goes down to 10, which is the lowest. These three factors, when combined with the carats in the diamond, will produce the AGS grade.
The color is of utmost importance in the AGS certificate grading process, as it determines if the diamond is a 0 or a 10 on the grading scale and thereafter, the price is determined.
If the color grade of a diamond is 4, it means that it does not have as much color as one that has, let’s say a 6. If the color grade of the diamond is less, then it means that the diamond is rarer and therefore, is more expensive. With the AGS diamonds scale, the cut is determined first, then the color, the clarity and finally, the carat weight. If the diamond has the finest cut grade it can possess and is colorless as well, with no blemishes, or other imperfections, and the weight is one carat, then the notation would be (0/0/0-1.000) carats.
