When grading a diamond, a jeweller will use
The most important of the 4 C’s is the CUT of the diamond.
Everything from the angles of the cut, to the proportions, symmetry, and finish are what give the diamond its brilliance.
There is a great amount of pressure involved to create a diamond, therefore, it is not surprising to see inclusions on the inside of the diamond, such as clouds, feathers or crystals. Surface blemishes such as scratches and polish lines may also be apparent. The diamonds with the fewest inclusions are the clearest and most valuable as they are also the most rare.
The diamond is graded for clarity under 10x loupe magnification. Grades range from Flawless, being free of all inclusions, to diamonds which possess large, heavy blemishes and inclusions that are visible to the naked eye.
The term colour refers to either the presence of, or the absence of, the colour in the white diamond. Resulting from the composition of the diamond, colour will not change over time.
Jewellers use the GIA professional colour scale to grade the whiteness or colourlessness of the diamond. This colour scale begins at D, being the highest rating, and goes down the alphabet all the way to z to grade the stones.
Diamonds are measured in carats, where one carat is equal to 200 milligrams, or 0.2 grams. The word “carat” comes from the carob seed once used in ancient times to balance scales. The shape and weight of these seeds are so uniform, even today’s sophisticated instruments cannot detect more than three one-thousandths of a difference between them.