By Wade Abel, CG, Director of Gemological Services, AGS Laboratories
Recently we received a question that is important for our clients to understand. The inquiry was about the clarity grade AGS 7, which has two categories, AGS 7 (SI2) and AGS 7 (I1).
The AGS grading system uses a 0-10 grade scale for three of the 4Cs: Cut, Clarity, and Color. This is an easy way to understand where the diamond fits relative to others. The system is a deduction-based scale which means that 0 is the best grade and 10 is the worst. The AGS Ideal® 0 is well known as the highest possible AGS grade.
As the grades move down the scale, they represent wider ranges. Because of this, the standard industry nomenclature can represent quite a large range per grade. Using the AGS 0-10 grading scale, these wider ranges can be made more descriptive as they become divided.
Two industry-standard grades, SI2 and I1, are represented by four grades with the AGS grading system. This allows AGS Laboratories the ability to assign these diamonds a more descriptive grade. A diamond may receive a grade of “SI2” on a report from another lab, whereas that same diamond could receive a grade of “(SI2) AGS 6” or “(SI2) AGS 7” when graded at AGS Laboratories. This grade division is also used for the I1 range, “(I1) AGS 7” or “(I1) AGS 8.”
In the image below, notice that the AGS 7 has two designations (SI2 and I1). This gives the consumer a better understanding and provides the market with a better way to communicate what the consumer will experience when viewing the diamond.
Most consumers are concerned with a diamond’s face-up appearance to the unaided eye, that is, the beauty of a diamond in everyday life. No two diamonds are exactly alike and the degree of inclusions in diamonds within the SI2 to I1 range can vary greatly. Observing a diamond in an overhead lighting environment, which most diamonds in jewelry are viewed, the darker, high-relief characteristics are more eye-visible.
Accepted grading practices for the industry assess clarity based on 10x magnification. All grading at AGS Laboratories is determined with this standard. However, to further the accuracy of the lower, possibly eye-visible grades, the appearance of the diamond to the unaided eye is taken into consideration.
The AGS Grading Standards for grades AGS 6, AGS 7, and AGS 8
The AGS Grading System defines the grades of AGS 6, AGS 7, and AGS 8 as follows:
- AGS 6- Noticeable inclusions that are very easy to see with a 10x loupe.
- AGS 7- Obvious inclusions that are apparent with a 10x loupe and often visible to the unaided eye.
- AGS 8- Obvious inclusions are easily visible to the unaided eye and may have an effect on durability.
On an AGS Laboratories report, the AGS grade is always accompanied by the industry-standard grade in parenthesis for reference.
For example:
- AGS 6 (SI2)
- AGS 7 (SI2)
- AGS 7 (I1)
- AGS 8 (I1)
A diamond with larger fields of minor inclusions (i.e., clouds, small crystals, twinning wisps, etc.) could be considered “busy” and can exhibit a duller appearance. These inclusions may not be visible to the eye, however, together they affect the overall appearance of the diamond. This is an additional consideration when grading lower clarity diamonds.
AGS Laboratories grades the diamond with the consumer in mind, to provide a consistent representation for the supplier, retailer, and consumer. When using the precise grade descriptions offered with the AGS scale, the diamond’s appearance can be easily communicated. The consumer has a better understanding of what to expect when purchasing a diamond. The AGS mission of consumer protection is perpetuated with this precise communication.
For more information on the AGS grading system, contact [email protected].
