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The 4C’s of Diamonds

Cut, Colour, Clarity and Carat.

4C’s of diamonds is a system created by GIA (Gemological Institute of America) that serves as the universal language when it comes to assessing a diamond’s quality.

When it comes to choosing a diamond, it is worth getting familiar with these four factors to make an informed decision.

While this list is in order of importance, it should be kept in mind that the 4C’s interact with one another. A diamond's true value is worked out by the combination of these four qualities.


This is the most important metric because it maximises brilliance and sparkle. It’s the cut of a diamond that defines its value the most, because it affects how the stone interacts with light. If the cut is too shallow or too deep even a flawless clarity diamond can look dull.

There are 3 types of diamond cuts: brilliant, step and mix cut:

Cushion, Oval, Marquise, Pear and Heart-shaped diamonds are all cut using the brilliant faceting style, the Round Brilliant being the most popular of them all.

The most well-known step cut is the Emerald cut, followed by Asscher and Baguette cut.

The Princess cut has become the most successful mixed cut as it wastes the least of the original stone. Another favoured mixed cut is Radiant.

While choosing a diamond it is important to have a high quality cut while maintaining a fine balance between colour and clarity.


Diamonds come naturally tinted in a number of hues depending on which foreign elements were present during their natural formation process.

Normal colour diamonds are graded from D (colourless) through Z (light yellow), D being the clearest colour and the most valuable.

Fancy colour diamonds (such as yellow, orange, red and blue) are graded on a separate system similar to the one used for coloured gemstones.

Colourless diamonds are the rarest and the most expensive. However, you can choose to go with a nearly colourless grade to leave room in your budget for the perfect cut to get more sparkles.

Colour is easier to perceive as the carat increases.

It is worth considering that once a stone is set in a ring it may appear a different colour. Yellow gold makes the yellow hue of a diamond less obvious.


Clarity indicates the purity of the stone. Since they are naturally formed within the earth under intense heat and pressure, all diamonds possess some impurities.

A diamond’s clarity ranges from FL (flawless) which reflects the most light, to I3 where the stone features inclusions (internal defects) and blemishes (surface flaws).

Clarity carries the least importance because most imperfections are not easily visible to the naked eye, although the inclusions in I1, I2 and I3 diamonds may be visible. This makes SI and VS diamonds the best value.

Emerald and Asscher-shaped diamonds require a clarity grade of VS1 or better as they have a deep cut which makes the inclusions more visible. Other shapes of diamonds such as Round, Princess, Oval, Marquise, Pear, and Heart-shaped have more tolerance.


Diamonds are measured in carats. Contrary to popular belief, carat refers to a diamond's weight, not its size. The heavier the stone, the more expensive it is. Two stones of the equal size can defer in weight.

When there is more than one diamond on a piece of jewellery such as a diamond cluster ring, total carat weight (CTW) is measured by weighing all the diamonds.

Half carat, three-quarter carat, and carat are known as "magic sizes". Although the eye doesn't perceive a difference between 0.99 carat and a full carat, the price significantly changes.

When deciding on a diamond's carat for a diamond ring, the size of wearer's finger should be considered along with the shape which it will be cut into.


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