Diamond Basics

Color 

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. 

Cut 

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. 

Clarity 

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. 

Carat Weight 

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. 

Laboratory-grown diamonds 

A lab-grown diamond (sometimes called man-made or synthetic diamond) is the result of a technological process, as opposed to the geological process that creates natural diamonds. Lab-grown diamonds have essentially the same chemical composition, crystal structure, optical and physical properties of diamonds found in nature. Most lab-grown diamonds are categorized as either high-pressure, high-temperature (HPHT) or chemical vapor deposition (CVD) diamonds, depending on the method of their production. Since HPHT and CVD diamonds grown in a laboratory are virtually identical to natural diamonds, differences only become clear when they are analyzed in a gem laboratory. 

GIA Grading Report

The GIA Diamond Grading Report includes an assessment of a diamond’s 4Cs – Color, Clarity, Cut and Carat Weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. The GIA Diamond Dossier® includes these without the graphical representation of the clarity characteristics. The GIA laboratory issues diamond grading reports for loose, natural diamonds in the D-to-Z color range that weigh 0.15 carats or more.

A diamond grading report is the scientific blueprint of a stone’s quality characteristics. A GIA diamond grading report is your assurance that your diamond is a natural diamond, with disclosure of any treatment to enhance color or clarity. All GIA reports contain security features to prevent them from being forged or duplicated. GIA does not buy or sell diamonds, making an independent diamond grading report from GIA an unbiased assessment of the diamond. 

Inclusions 

Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions.’ Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader. This is why expert and accurate assessment of diamond clarity is extremely important. 

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

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

• 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): Minor Inclusions that range from difficult to somewhat easy to see are visible to a skilled grader using 10x magnification 

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