The Cut of a diamond is the one 'C' governed by man’s skill rather than by nature and it has a significant influence on the value of a diamond. The true beauty of a diamond is its ability to reflect light, which makes cutting from rough gems a highly complex process taking great skill. If a diamond is cut too deep, light escapes from the base and brilliance is lost and the diamond appears dark. A very shallow cut results in light escaping from the bottom of the stone, causing it to lose brilliance, making the diamond look glassy. However when a diamond is cut to perfect proportions, light entering from any direction is reflected through the top of the stone giving it more fire and brilliance.
Diamonds are graded according to the four characteristics that determine their value – the Cut, the Colour, the Clarity, and the Carat.
The Colour of a diamond also affects its value because diamonds are found in tints covering the entire spectrum, ranging from a pale yellow or brown tint to the rare, much sought after ‘colourless’ white. Diamonds are graded according to their inner body hue using a white to yellow scale. The whiter a diamond, the more rare and valuable it is.
The Clarity is based on the fact that diamonds contain minute traces of non-crystallised carbon from which they originate. These traces or ‘inclusions’ are nature’s fingerprints or natural imperfections that make each diamond unique, and in gem-quality diamonds, they are usually only seen under magnification. In principle, the fewer the inclusions, the finer the Clarity and the more valuable the stone.
The Carat is the size or mass of a diamond. One carat is divided into 100 points, so 25 points is a quarter-carat. And although size is the most obvious factor determining the value of a diamond, two diamonds of equal size can have very unequal values depending on their quality.