Most diamonds in North America are classified according to the 4 c's- carat, colour, clarity, and cut.
Carat is the system of measuring the weight of a diamond. Historically, it derives from the carob seed, a small uniform seed that early gem traders used to balance their scales. Like the Canadian dollar that is comprised of 100 cents, each carat is divided into 100 points. Therefore, a one third carat diamond can also be referred to as 0.33 points and a 10 point diamond is ten 100ths of a carat. Two diamonds of the exact same weight can have widely differing values depending on their colour, clarity and cut. The larger the diamond, the more rare it will be and therefore, more expensive.
Colour is a grading system that determines how closely the diamond comes to being colourless; the less colour, the more valuable the gemstone. Based on a scale starting at D and ending with Z, they are compared to a master set of diamonds of known colour under controlled lighting and conditions. Natural diamonds can range in colour from translucent white to those with hues of pink, brown, and yellow; fortunately, Canadian diamonds are renowned for their near colourless beauty. Fancy coloured diamonds have their own colour grading definitions.
Clarity is the measure of the absence of inclusions (internal) and blemishes (external) in a natural diamond. Using 10 x magnification, gemologists determine the type, size and location of the diamond's characteristics and assign a grade.
Cut refers to the diamond's proportion (how the diamond's angles and facets relate to one another), symmetry (the precision of the cut) and polish (the condition of the diamond's surface).
While nature provides the diamond with its colour, clarity and carat weight, it is the skilled diamond cutter that unleashes the inner fire and beauty. In a well cut diamond, the light will internally reflect from one mirror-like facet to another and will send that light through the top of the stone to your eye, thereby creating the lively, brilliant sparkle that is so desirable.
If the stone is cut too deep, some light escapes through the opposite side of the diamond. If it is cut too shallow, the light will escape through the bottom of the diamond before it can be reflected. Cutting grades run from Ideal, to excellent, very good, and good to poor.