4 Cs of Diamond Buying

The 4 Cs are globally accepted as a standard for describing and reviewing diamonds and includes the Colour, Clarity, Cut, and Carat Weight.

Diamond Colour
A pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. The D-to-Z diamond colour-grading system measures the degree of colourlessness by comparing a stone under controlled lighting and precise viewing conditions to masterstones of established colour value.

Many of these distinctions are so subtle that they are invisible to the untrained eye; however, they make a big difference to the diamond quality and price. You can check the value of your diamond by using our diamond price calculator on our website. If you need to speak to someone, our experts can help you quickly identify your diamond colour.

Diamond Clarity
The clarity of a diamond refers to the absence of inclusions and blemishes. When evaluating diamond clarity, you are determining the number, size, relief, nature, and position of these inclusions, as well as how they affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.

The Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.

• Flawless (FL)
• No inclusions or blemishes visible under 10x magnification
• Internally Flawless (IF)
• No inclusions visible under 10x magnification
• Very, Very Slightly Included (VVS1 and VVS2)
• Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
• Very Slightly Included (VS1 and VS2)
• Inclusions are observed with effort under 10x magnification, but can be characterized as minor
• Slightly Included (SI1 and SI2)
• Inclusions are noticeable under 10x magnification
• Included (I1, I2, and I3)
• Inclusions are obvious under 10x magnification which may affect transparency and brilliance

Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader. To the naked eye, a VS1 and an SI2 diamond may look exactly the same, but these diamonds are quite different in terms of quality. This is why expert and accurate assessment of diamond clarity is important.

Diamond Cut
Diamonds are renowned for their ability to transmit light and sparkle. We often think of a diamond’s cut as shape (round, emerald, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light. 

To determine the cut grade of a round brilliant diamond – the shape that dominates the majority of diamond jewellery – we calculate the proportions of those facets that influence the diamond’s face-up appearance. These give an indication of how successfully a diamond interacts with light to create desirable visual effects such as:

• Brightness: Internal and external white light reflected from a diamond.
• Fire: The scattering of white light into all the colours of the rainbow.
• Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond.

The diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond colour range contains 5 grades ranging from Excellent to Poor.

Diamond Carat Weight
Diamond carat weight is the measurement of how much a diamond weighs. A metric carat is defined as 200 milligrams.

Each carat can be divided into 100 points. This allows very precise measurements to the hundredth decimal place. A jeweller may describe the weight of a diamond below one carat by its points alone. For instance, the jeweller may refer to a diamond that weighs 0.25 carats as a twenty-five pointer. Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as 1.08ct.