Diamond Learning

Diamond Buying Guide – The 4 Cs

Gem experts judge the quality and value of a diamond by using four criteria called the 4 Cs – Cut, Colour, Clarity and Carat weight. Below, we’ll explain each of these quality factors, with recommendations that will help you choose the best diamond jewellery for you.

1. CUT

Cut is arguably the most important of the 4 Cs because the diamond’s sparkle depends on it. A diamond’s cut refers both to its shape, as well as the skill with which it has been carved into a gemstone. The cut is the only aspect of a diamond that relies solely on man (rather than nature). Only a skilled craftsman can cut and polish a rough stone into a beautiful diamond.

Diamonds can be carved into many different shapes, ranging from round to geometric, and even fancy cuts like hearts. Read more about this topic in our article about diamond shapes.

Diamond Buying Guide: Looking Through the Jeweller’s Loupe

On the other hand, the quality of a diamond’s cut, and how it plays with light, is graded as follows:






OUR RECOMMENDATION: Always choose a cut quality that’s either GOOD or VERY GOOD. This will ensure your diamond exhibits beautiful lightplay and sparkle. If you’re in doubt about the shape, you cannot go wrong with a classic round cut, which is the sparkliest diamond shape of them all.


All diamonds are graded by colour. This may sound confusing, as diamonds are transparent. However, a very poor-quality diamond will actually look noticeably yellowish, even to the naked eye. Diamonds are judged on a colour scale from D to Z. This means that the best colour grade is D which is colourless, and the worst is Z which is very yellow:

OUR RECOMMENDATION: For solitaire diamonds under 0.50 carat, choose colour grade H. It is within the white colour range, so the naked eye cannot tell if there is any yellow in it. Additionally, it’s a very affordable diamond colour which offers you great value for money.


Without clarity, a diamond will look dull and lifeless. What is clarity? Inside most diamonds, there are small mineral flecks or tiny fractures. These naturally occurring marks are called inclusions. The fewer inclusions a diamond has, the better its clarity – and the more expensive the diamond. Diamond clarity is measured in units from IF (Flawless) which is the clearest, to I3 (Included) which is the least clear.

Diamond clarity chart

OUR RECOMMENDATION: If you’re buying a diamond under 0.50 carat, stick within the clarity range from SI2 (Slightly Included) to VS1 (Very Slightly Included). With these clarity grades, you’ll get good value for money because you will not be able to see any imperfections with the naked eye.


A diamond’s weight is measured in carats. The more carats there are, the bigger the diamond. There are 100 points in each carat. This means, for example, that if a diamond weighs 100 points, it will be 1 carat in size, and this would be indicated as 1.00CT when you’re shopping for jewellery. On the other hand, if a diamond weighs 50 points, then it will be half a carat in size. This would be written as 0.50CT.

A diamond’s size is not necessarily an indicator of quality. For instance, a small diamond with good clarity, cut and colour than a large diamond with poor clarity, cut and colour. Therefore, it’s best to not focus too much on carats, until you have decided on the other 4 Cs.

OUR RECOMMENDATION: Always choose the carat weight last. If you’ve chosen the cut, clarity and colour of your diamond, and still have money left in your budget, then you can add more carat weight to your diamond.

A couple more things worth considering…

Apart from the 4 Cs, we like to remind diamond buyers about two further Cs – certificates and conflict-free diamonds.

1. Certified diamonds

A certified diamond comes with a diamond report, also called a diamond certificate, from a gemmological institution such as the GIA or the IGI. A diamond report adds value by confirming your diamond’s four Cs and other characteristics, plus proving ownership. Read more about diamond certificates here.

2. Conflict-free diamonds

Make sure you buy conflict-free diamonds. This means that your diamond does not come from the black market or has been sold for profit by illegal groups or terrorists that commit human rights violations. Read more about conflict-free diamonds here.

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