The 4Cs

With its unparalleled access to the world’s most beautiful diamonds, De Beers has been the diamond expert since 1888. As the only jewellery House to select all our diamonds by eye, we also uphold the highest industry standard for cut quality. Masters of their craft, our diamantaires assess the Fire, Life and Brilliance of each diamond, as well as its silhouette, determining its value with the help of the Four Cs.

Cut

The cut of a diamond is paramount, as a perfect cut will maximise its sparkle. A well-cut diamond can command a higher value than a poorly cut diamond, even if larger in size or rarer in colour.

A diamond should be cut with perfectly symmetrical, aligned facets – a skill requiring vast technical expertise and refined artistry. The GIA will grade a diamond from Excellent to Poor: if excellently cut, the diamond will reflect light internally from one mirror-like facet to another, dispersing it through its uppermost surface, or the ‘table.’ It’s the final polish that gives the diamond its shining outside finish.

At De Beers, we meticulously hand-select or cut every one of our diamonds, assessing them with an expert, trained eye. Accepting only top cut grades, we require the perfect alignment of facets and angles for that ultimate sparkle.

Colour

White diamonds are graded on a scale of 23 shades, ranging from rare ice white D (colourless) to the warmer Z (light colour). Beyond this colour palette, diamonds are classified as Fancy Colours.

The difference between one diamond’s shade and the next is very subtle, therefore, we grade in a laboratory under controlled lighting. Placing the polished diamond upside down, our experts use master samples for comparison and accuracy. Even so, the ‘face up’ colour of a diamond can be quite different, possibly even much brighter if its sparkle is very prominent. But every colour shade of diamond has its own beauty.

At De Beers, we carry the full range of colours to give our clients more choice. We see the colour grade of a white diamond as an indication of its rarity rather than its desirability.

Carat

Carat is a measurement of weight, with one diamond carat equal to 200 milligrams. ‘Carat’ derived from the word ‘carob’; in ancient times, carob seeds were used as a reference for diamond weight. Today, precise measurements are taken to the hundredth decimal place to ensure complete accuracy.

The carat weight by itself does not determine a diamond’s value. Two diamonds of equal carat weight may have very different values based on the other factors: all the 4Cs have an influence on each other in diamond grading. At De Beers, we always cut for maximum beauty, never for weight, so a De Beers diamond is always spectacular.

Clarity

Clarity refers to a diamond’s natural ‘inclusions.’ Natural diamonds were originally created by extreme heat and pressure deep within the earth, millions, even billions, of years ago. This organic process means that just about all diamonds contain inclusions such as traces of minerals or uncrystallised carbon. Inclusions do not affect the structural stability of a diamond.

Even when invisible to the naked eye, inclusions and blemishes can still influence the way light is reflected and refracted, which is why their shape, size, and position are taken into account in diamond grading. Diamonds with fewer inclusions have a higher clarity, ranging from the very rare FL (flawless internally and externally) to I (with significant inclusions and blemishes). De Beers only chooses white diamonds up until the grade SI2, meaning that their inclusions are only visible under magnification.