When you are planning on purchasing a diamond it is important that you know as much as possible about how diamonds are classified. Various characteristics of diamonds are grouped and identified by the diamond industry. Learning about the “Four Cs” (Cut, Clarity, Colour, and Carat), which are considered the most important categories, is the first step to learning about diamonds. The price of two diamonds of the same cut can vary due to the differences in clarity, colour, and carat.


The cut of a diamond refers to the symmetry, proportioning, and polish of a diamond. The cut of a diamond impacts a diamond’s brilliance; this means if it is cut poorly, it will be less brilliant. Every diamond gets its luminosity by being cut and polished to allow the maximum light to be reflected and dispersed throughout the stone. A diamond that is cut too shallow or deep does not allow the maximum potential of the diamond to be observed.


Most diamonds contain some inner flaws, known as inclusions, that occur during the formation process. The number, size, location, and visibility of these inclusions determine what is called the clarity of a diamond. Diamonds that are clear create more brilliance, and thus are more highly prized, and priced. Large inclusions can affect a diamond’s ability to reflect light. Minor inclusions or blemishes are useful, as they can act as unique identifying marks. As it becomes difficult to distinguish between natural and synthetic diamonds, inclusions or blemishes can be used as proof of natural origin.


Jewellers most commonly use the letters D to Z (colourless to very light yellow) when rating the colour of a diamond. As a rule, the closer a diamond is to colourless, the more valuable and beautiful it is. For example, most diamonds are priced inexpensively when more yellow hue is detectable, while colourless, intense pink or blue diamonds can be dramatically more valuable.


Carat is a unit that specifically measures the weight of a diamond, and by itself may not accurately reflect a diamond’s size. As the carat of a diamond rises, so does its rarity and the price. One carat is divided into 100 points, therefore, a diamond that is 50 points would be .50 carats.