Diamonds are usually sold by carat (ct). One carat is the equivalent size of 0.2 grams. The bigger the diamond, the rarer it is. Price is determined based on perfection of the four C’s. Shapes such as the Oval, Marquise, Pear and Emeralds may have the same weight as the rounds and squares but they may appear smaller based on how they are cut.
The sparkle and brilliance of a diamond is determined by the precision of the cut. This, in turn, influences the pleasure of looking at the finished jewelry.
Each gem is graded based on its lack of color, apart from fancy color diamonds where the color adds to its value. The scale starts at D, the highest level of lack of color, and ends with Z.
Clarity is based on how noticeable the imperfections are. The less visible the flaws are, the better. Inclusions are flaws within and blemishes are flaws on the surface of the diamond. Inclusions and blemishes interfere with the light that passes through the stone, causing the diamond to shine less.
Diamond certificates are issued by accredited gemological laboratories to ensure that all the details of the diamonds are valid.
A diamond certificate can also be identified as diamond grading report, or a diamond dossier®.
The most common grading laboratories are:
Gemological Institute of America (GIA)
International Gemological Institute (IGI)
European Gemological Laboratory (EGL)
Hoge Raad Voor Diamant (HRD)
Each certificate has the information that was collected throughout the analysis, which reflects the 4 C’s.