Carat is the measurement of diamond weight. A carat is equal to 100 points. For instance, a 0.5 carat diamond would be described as a “fifty pointer.” The larger a diamond is, the more rare and precious it is. But two diamonds of equal carat weight can differ greatly in value depending on their colour, clarity, and cut.
Exquisite craftsmanship is the key to an ideal-cut diamond. A diamond with optimum proportions and fine polish can result in a magnificent display of its brilliance. An ideal-cut diamond reflects light from one mirror-like facet to another and disperses it through the top of the stone, giving the diamonds its maximum brightness, fire and value. A round brilliant cut diamond, for example, has 57 or 58 facets. Round, oval, marquise, heart, pear and square are the common shapes in diamond jewelry.
Most diamonds run through colourless to near-colourless. The colour grading scale of diamonds ranges from D to Z, with D representing colourless and Z standing for light yellow. The price of a diamond decreases with increasing of yellow hue.
Among the 4Cs, colour is the determining factor in the value of a fancy colour diamond. Colour is described in terms of hue, tone and saturation. Fancy colour diamonds are graded by different colour categories such as Fancy Light, Fancy, Fancy Deep, Fancy Intense and Fancy Vivid. The more intensely coloured a fancy diamond is, the more valuable it becomes.
Diamond is a natural mineral that often contains inclusions and black blemishes. In determining a clarity grade, the number, size, shape, colour and position of inclusions and blemishes are examined under 10x magnification. The fewer inclusions and blemishes a diamond has, the higher its clarity grade and price are. The clarity grading scale consists of 11 grades: FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2 and I3. Flawless diamonds are exceptionally rare. As no two diamonds have exactly the same inclusions and blemishes, these clarity characteristics may be used as the unique marks for identifying individual diamonds.
The clarity grading scale consists of 11 grades: