Because diamonds are so valuable, it’s essential for industry professionals to have a universal grading system when comparing diamond quality. In the mid-twentieth century, GIA developed the International Diamond Grading SystemTM and the 4Cs as a way to objectively compare and evaluate diamonds.
The Four Cs of diamond quality will give you a multitude of information about a diamond’s characteristics and value, but they can’t begin to describe one elusive quality – beauty. To do that, you’ll need to experience the diamond with your own eyes.
When diamonds come from the earth, they look nothing like the polished and cut gems you expect to see in fine jewellery. A lot of work goes in to turning these rough diamonds into perfect works of fiery brilliance. Cut and Shape are often confused – Shape refers to the outward appearance of the diamond (such as round, emerald, princess etc). Cut refers to the reflective qualities of the diamond.
When a diamond is well-cut, light enters through the table of the diamond, travels to the pavilion and reflects from one side to the other before reflecting back out of the diamond through the table. This light creates a flashing effect that we know as brilliance/sparkle.
Cut is described with the following grades:
Ideal, Excellent, Very Good, Good, Fair, and Poor.
Some diamond certificates do not specifically state the ‘Cut’ grade of the diamond. As we use a variety of independent certificates (mostly GIA and IGI) we cannot guarantee that the cut grade will appear on your certificate. It bears no reflection on the quality of the stone you have purchased if your certificate does not state the grade, as your diamond will always be ‘Very Good’ or better. It requires a trained eye to judge the quality of a diamond cut, and our in-house diamond graders are highly qualified professionals who only select diamonds that they grade as ‘Very Good’ or better. Your diamond will be well-cut, bright and sparkly, we guarantee it!
As with all precious stones, the weight – and therefore the size – of diamonds are expressed in carats. The carat originated as a natural unit of weight: the seeds of the carob tree. Diamonds were traditionally weighed against these seeds, however, the system was later standardized and one carat was fixed at 200 milligrams (1/5 of a gram).
One carat is divided into 100 “points” so that a diamond of 25 points is described as a quarter of a carat or 0.25 carats. Size is the most obvious factor in determining the value of a diamond, though two diamonds of equal size can have unequal prices, depending on their quality. Diamonds of high quality can also be found in all size ranges.
Carat Weight has no bearing on a diamond’s colour or clarity. It does, however, have a significant impact on Cut.
The most desirable diamonds are those which have the least amount of colour. Quite often however diamonds will have a tint of yellow or brown. Generally, diamond colour can be divided into four categories.
Of the 4 C’s colour can be the most confusing to understand. It’s not until you get to the I-J range and onwards that you start noticing hints of colour and even so it depends on how you are viewing the diamond. When viewed face up the diamond will appear perfectly white however when viewed face down against a completely white background you will be able to detect the colour much more easily. Near colourless diamonds are more common and offer great value for money.
This refers to the presence of inclusions in a diamond. Inclusions are natural identifying characteristics such as minerals or fractures, that appear while diamonds are being formed. They may look like tiny crystals, clouds or feathers. Inclusions are usually viewed at 10x magnification.
The position of inclusions can greatly affect the value of a diamond. Some inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, making the diamond less brilliant. Inclusions are ranked on a scale of perfection known as the clarity scale. The scale ranges from F (Flawless) to I (Included) and is based on the visibility of inclusions at 10X magnification. In addition each basic grade is followed by the number 1,2 or 3 to indicates the severity of the inclusion(s).
The basic rule of thumb is if you can see the inclusion(s) with your naked eye then it is an “I” grade stone. If you can’t see an inclusion with your naked eye it is either an IF, VS or SI grade stone (AKA – eye clean) & will need to be viewed with 10x magnification loupe to further determine the grade. If you can easily see it with a 10x loupe then it falls somewhere into the SI grade & if a 10x magnification doesn’t show the inclusion then you’ll need further magnification to narrow the grade to VS or IF.