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.
The weight of diamonds, and all other gemstones, is measured in carats
Table width is quoted as a percentage of the average width of the diamond's girdle
The total depth percentage is greatly responsible for the amount of brilliance that a diamond will display
The pavilion is the bottom portion of the diamond
The point on the bottom of a diamond's pavilion is called a cule
Roughly one third of diamonds available in the market fluoresce
Symmetry is graded as Excellent, Very Good, Good, Fair or Poor on a GIA report
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