Diamond Color, Clarity, Cut and Carat Weight are collectively termed the 4Cs – the factors that, when combined, define a diamond’s quality and ultimately determine its value. GIA created the 4Cs of Diamond Quality, which has become the universal method for assessing the quality of any diamond, anywhere in the world. The creation of the 4Cs means that diamond quality can be communicated in a universal language so diamond purchasers know exactly what they are buying. 

GIA’s diamond color grading system measures the absence of color, starting with D as colorless and continuing to Z representing light yellow or brown. The distinctions between color grades are so subtle that they are often invisible to the untrained eye but can make a big difference in diamond quality and price. 

A diamond’s cut determines its sparkle. To fashion a stone with proportions, symmetry and polish worthy of an excellent cut grade requires artistry and workmanship. The finer the cut quality, the more sparkle the diamond has. 

Natural diamonds form from carbon exposed to tremendous heat and pressure deep in the earth. Diamonds often contain clarity characteristics, called inclusions or blemishes. Inclusions are enclosed within the gem and blemishes are on the surface of the diamond. If all else is equal, the closer a diamond is to flawless, with no inclusions or blemishes, the higher its value. 

Flawless (FL)

Flawless (FL): No inclusions and no blemishes are visible to a skilled grader using 10x magnification

Internally Flawless (IF)

Internally Flawless (IF): No inclusions and only blemishes are visible to a skilled grader using 10x magnification

Very, Very Slightly Included (VVS)

Very, Very Slightly Included (VVS): Minute inclusions that range from extremely difficult to very difficult to see are visible to a skilled grader using 10x magnification

Very Slightly Included (VS)

Very Slightly Included (VS): Minor Inclusions that range from difficult to somewhat easy to see are visible to a skilled grader using 10x magnification

Slightly Included (SI)

Slightly Included (SI): Noticeable inclusions that range from easy to very easy to see are visible to a skilled grader using 10x magnification

Included (I)

Included (I): Obvious inclusions are visible to a skilled grader using 10x magnification and may affect transparency and brilliance 

Diamond weight is measured in carats. One carat is equal to 0.2 gram, about as heavy as a paperclip. Since larger diamonds are more rare, they will cost more than a smaller gem with the same color, clarity and cut grades.