Diamond Grading Terminology

A diamond's cost is based on the characteristics known as the "4 C's". Clarity, Colour and Cut (proportion) are the quality elements which together with the Carat Weight determine the value of a stone. The closer a diamond grades to the left of one or all of these scales the rarer and the more costly it will be. While clarity is frequently assumed to be the most important factor of all the "C's", in fact, colour and cut (especially cut) have a more profound affect on the visual appearance of a diamond.

Clarity: The clarity grade of the diamond listed.

Color: The color grade of the diamond.

Cut: Proportions rating as determined by Sarin Analysis.

Carat Weight
The weight of diamonds, and all other gemstones, is measured in carats

Table Width
Table width is quoted as a percentage of the average width of the diamond's girdle

Total Depth
The total depth percentage is greatly responsible for the amount of brilliance that a diamond will display

Pavilion
The pavilion is the bottom portion of the diamond

Culet
The point on the bottom of a diamond's pavilion is called a cule

Fluorescence
Roughly one third of diamonds available in the market fluoresce

Symmetry
Symmetry is graded as Excellent, Very Good, Good, Fair or Poor on a GIA report

Polish
Polish is graded the same way as symmetry: Excellent, Very Good, Good, Fair or Poor on a GIA report

GIA: Gemological Institute of America - Gem Trade Laboratory (GIA-GTL)

AGS: American Gem Society Laboratory (AGSL)

EGL: European Gemological Laboratory