Understanding a AGSL Diamond Grading Report
A Diamond Quality Document, issued by the American Gem Society Laboratories (AGSL), is universally accepted and respected by the jewelry industry as a document of authenticated quality.
The AGSL uses a diamond grading system that ranks cut, color, and clarity on a zero to ten scale, with zero signifying the rarest and most desirable and ten indicating the least desirable.
Diamond Characteristics Documented by the AGSL ::
- Shape and Style :: Describes the diamond shape and cutting style.
- Measurements :: Lists the diamond's dimensions in millimeters.
- Cut Grade :: A grade of cut, zero being the rarest and most desirable and ten indicating the least desirable. There are three components that determine a cut grade: Light Performance, Proportion Factors, and Finish.
- Light Performance :: The overall appearance of a diamond when it is viewed from above. Light Performance is one of the three factors used to determine cut.
- Proportion Factors :: Factors which determine a diamond's shape, including the proportions, weight ratio and durability. Proportion Factors are one of the three factors used to determine cut.
- Finish :: The overall measure of a diamond's polish and symmetry. Finish is one of the three factors used to determine cut.
- Polish :: Rating the overall smoothness of the diamond's surface.
- Symmetry :: Measuring the shape, alignment and placement of the diamond's facets in relation to one another as well as the evenness of the outline.
- Color Grade :: A grade of color, zero (D) being the most rare and desirable and ten (Z) being the least desirable. Assigned half points to accommodate all the grades of color.
- Clarity Grade :: A grade of clarity, zero (FL/IF) being the most rare and desirable and ten (I3) signifying the least desirable. Look in the comments section for remarks about the finish.
- Carat Weight :: Diamond weight is measured to the third decimal place.
- Comments :: A description of additional diamond characteristics not already mentioned in the report, as well as fluorescence, which is rated on a scale and categorized using the words inert, faint, medium, strong, very strong.
- Proportion Diagram :: A map of the diamond's actual proportions which typically include the following information ::
- Depth :: The height of a gemstone measured from the culet to the table.
- Table :: Located at the top of the diamond, the table is the largest facet of a diamond.
- Girdle :: Range of girdle thickness.
- Culet :: Appearance, or lack thereof, of the culet facet.
- Clarity Plot:: A map of the approximate size, type, and position of inclusions as viewed under a microscope.
Oct-13th-2008
This diamond grading system will ranks 4C's on a zero to ten scale according to their quality. zero signifying the most desirable and ten indicating the least one.