Diamond 4 C's

Every diamond is an individual miracle of time and place and chance. Like snowflakes, no two are exactly alike.

Until the middle of the twentieth century, there was no agreed-upon standard by which diamonds could be judged.

The GIA (Gemological Institute of America) created the first, and now globally accepted standard for describing diamonds: Colour, Clarity, Cut, and Carat Weight. We now accept the 4Cs of Diamond Quality as the universal method for assessing the quality of any diamond, anywhere in the world.

The Diamond 4Cs means that diamond quality can be communicated consistently in a universal language, and diamond customers know exactly what they are purchasing.

When graded by the major recognised authorities – GIA, HRD, AGS & IGI, The 4C’s are the deciding factors in combination that set the price. But remember other factors can influence the price – such as retail mark-up, designer brand etc.

We also believe there is an important 5th C – Certification. This provides Independent assurance that you’re getting a quality diamond that is accurately graded without bias.


Diamond carat is often misunderstood and refers to a diamond’s weight, not necessarily its size, the carat weight measures the mass of a diamond. One carat of diamond equals 0.2 gr.

When comparing diamond carat sizes, you need to take a diamond’s cut into consideration. A high-carat diamond with a poor cut grade may look smaller, and is often cut deeper, than a diamond with smaller carat weight and a better cut.

Don’t let this be confused with the term Karat, which refers to gold and is a unit for measuring its fineness. 24 Karat gold is considered 100% gold, so other alloys are proportional to their gold content. For example the popular 18 karat gold is 18/24 = 75% pure gold (with 25% being the alloy).


Diamond clarity is the assessment of any imperfections on the surface and internally so refers to the presence of internal and external characteristics in a diamond.  The surface flaws are called blemishes, and internal defects are known as inclusions.

Most diamonds have blemishes and small inclusions that are microscopic, and unable to be seen with an untrained or unaided eye. These tiny, natural blemishes and inclusions therefore do not affect a diamond’s beauty in any way. Diamonds with the least and smallest inclusions are recognised with the highest clarity grades and of course demand higher prices.

There are eleven diamond clarity grades FL, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2  and I3. These range from Flawless to Internally Flawless, through to Very Very Slightly Included, then Very Slightly Included, to Slightly Included and finally to Included.

A diamond is Internally Flawless when no inclusions are found when inspected by the trained eye using a 10x loupe.

The first 5 to 7 levels of clarity look identical to the naked eye! When SI1 or SI2, the nature and position of the inclusions determine whether the diamond is eye-clean or not. Therefore,


The diamond colour is an important characteristic to consider when choosing a diamond. There are six categories on the diamond chart, with colour grades that range from absolutely colourless to light in colour. The highest quality diamonds are colourless, while lower quality diamonds have a noticeable yellow colour.

The colour of a diamond can range from D (colourless) to Z (light yellow or brown). The sequence follows the letters of the alphabet, excluding A,B, and C.

Diamonds rated D are the most devoid of colour and very rare, whereas G colour diamonds and H colour diamonds are near colourless. When set in a piece of jewellery, the first six colours (D-I) pretty much look alike when ‘face-up’. This makes the near colourless diamonds (G and H) which are priced lower excellent value diamonds.

The further you move down the colour chart, the lower the colour grade and the more noticeable the light yellow hue becomes. We provide Colourless and Near-Colourless diamonds so that any natural colour present is typically undetectable to the naked eye.



Cut is the most underestimated element of the 4C’s and refers to the angles and proportions of a diamond. Cut also refers to the finishing qualities, being symmetry and polish.

The cut is the biggest factor when creating sparkle and fire, and without a high cut grade even a diamond of high quality with perfect clarity and colour grade, can appear dull and lifeless.

A good diamond cutter will make sure the diamond has a maximum ‘Light-Performance’ i.e. the sparkle.  When diamond cut is made with the proper proportions, light is returned out of the top of the diamond (the table). If the cuts are too shallow, light leaks out of the bottom; too deep and it escapes out of the side. A diamond cut poorly and too deep can face-up smaller than it actually is.

To maximise your budget, choose the highest diamond cut grade your budget allows. We only provide the highest cut grade.

Independent Diamond Certification

Many clients purchasing for the first time wonder what is diamond certification, and how are diamonds independently certified?

Independent certification is your assurance that you’re getting a quality diamond that is accurately graded without bias.

All our diamonds (from 0.35 carat upwards) are accompanied by a worldwide accepted diamond grading reports from internationally recognised bodies such as HRD, GIA, AGS or IGI.

The GIA (the oldest and the strongest in the US), the HRD (HRD is strong in Europe and the Middle East/Dubai) and the IGI (the largest gem-lab worldwide that specialises in grading diamonds up to 0.99ct). This way you have independent verification of the quality of the diamond.

Rob van Beurden founder of Diamond House handpicks the best cut diamonds is a member of the main Diamond Bourse in Antwerp Member Number: VAN2414. It is also the oldest Diamond Bourse in the world. There are only 1500 members worldwide across 23 countries and is the highest honour, privilege and responsibility as members are bound by a strict code of ethics. For more information, see Antwerp Diamond Bourse. https://www.diamondbourseantwerp.com/

All our diamonds of 0.35 carat and above are laser inscribed with the report number on the girdle of the diamond, so you can be assured that the loose diamond you chose matches the accompanying grading report.

The laser inscribed number is so small that it can be viewed only with x14 loupe and so it does not affect the light-performance of the diamond in any other way.

We guarantee that our diamonds are “conflict-free” by purchasing our diamonds from legitimate sources not involved in funding conflict and in compliance with United Nations resolution, based on personal knowledge and/or written guarantees provided by our diamond suppliers.

All our diamond jewellery comes with free aftercare service including any re-sizing of rings (except for full diamond eternity bands which have to be made exactly to size). To keep your jewellery looking at its best, you should get your piece serviced (clean, polish and re-check diamond claws) at least every 2 years.