The 4 Cs

The 4 Cs (Clarity, Colour, Cut and Carat Weight) are the main factors by which the diamond industry evaluates a diamond's physical attributes.It's very important to understand this basic terminology, as it is the mode by which diamond dealers rate diamonds comparatively, and the way in which diamonds are evaluated by laboratories which issue Diamond Grading Reports. Understanding the 4 Cs will enable you to grasp the details that are listed in your diamond's Grading Report, and give you the 4 most important words in the vocabulary of the diamond industry.


Clarity in diamonds refers to their clearness and purity, how many impurities or blemishes occur both on the inside and on the surface of a diamond, and where they are positioned. A perfectly clear diamond is the most desirable, and will have the highest clarity rating. Every imperfection or colour flaw inside or outside the diamond will diminish its level of clarity, and therefore its value. Even fancy coloured diamonds have clarity ratings, and have a heightened value based on how perfect and even they are, and how many or few blemishes they include.


Colour refers to the colour scale of white diamonds, or the colour or colours of fancy diamonds. White diamonds can be completely colorless, or have a yellowish tone, but even the most yellow of white diamonds is far less colourful than a fancy yellow diamond. The less colour a white diamond contains, the more valuable it is, and the more highly rated it will be on the colour scale. Fancy diamond colours include red, blue, pink, green, orange, yellow, black and brown, and one diamond may include more than one colour. Fancy diamonds, being rarer than white diamonds, may be more valuable, depending on their level of purity and size.


Cut refers to the proportions, symmetry, finish, and polish of a diamond.  These are factors that influence the brilliance and reflective qualities of the diamond.  A poor cut generally refers to a cut which has offensive ridges that may interfere with the finished appearance of the diamond. A poor cut will muffle the brilliance, or sparkle, or a diamond, by preventing light from being dispersed evenly. The cut is the only one of the 4 Cs that is determined by artistry and not by nature.

Carat Weight

Carat refers to the weight of a diamond. The term itself is derived from the Carob fruit, whose evenly weighted seeds were used long ago as a comparative measurement for the weighing of diamonds and other small, but valuable, items. Contrary to popular belief, carat weight is not directly correlated to the size or a diamond.  One carat is equal to 0.20 grams, and is subdivided into 100 points. Larger diamonds are rarer than small diamonds, which means that each subsequent carat of weight makes a diamond successively more expensive with the value per carat increasing with the size of the diamond. An obvious example for this is that 0.50 carat diamonds are worth less than a single 1 carat diamond due to the natural rarity of larger rough diamonds.