Understanding the diamond 4 C's


Inclusions found within a diamond can be considered nature's birthmarks, the distinguishing characteristics that make the stone unique. When grading a diamond, the amount of inclusions and blemishes has a direct impact on its clarity and value. Flawless diamonds containing no inclusions are extremely rare and very expensive. A majority of the commercially sold diamonds contains inclusions that are undetectable to the unaided eye.

FL (Flawless) is the best clarity of diamond as it does not contain any inclusions or blemishes, under the scrutiny of 10x magnification. IF (Internally Flawless) diamonds may contain external characteristics (also known as blemishes) that are extremely difficult to view at 10x magnification on the stone's surface, if at all.

Pobjoy diamonds and diamond set jewellery range in clarity between IF and Si1.

Of equal significance is whether the diamond is eyeclean. This simply means that it appears to the naked eye as being free from inclusions or blemishes unless looked at under a loupe or magnifying glass.

While not included in a grading report, some diamonds can exhibit brown, green or milky undertones. This is known as BGM. It is important that the diamond you choose is appropriately screened to avoid this.


In simplified terms, the 'whiter' the diamond the better, with D being the most colourless. However, as can be appreciated from the colour table below, the naked eye will be pushed to identify any noticeable colouring until I.

It is also worth noting that some diamonds of similar GIA colour grading may display very subtle hints of brown, green or milkiness. That is why, among other variables (such as the nature of inclusions and cut) when comparing diamonds and prices there will invariably be some difference in market value between two apparently identically graded stones.

Pobjoy mainly supply diamonds between D and H.


Essentially the cut of a diamond measures how well it sparkles. Grading of the cut in descending order is Excellent, Very Good, Good, Fair or Poor. The cut grading currently only applies to round brilliant solitaire diamonds as they are quantifiably easier to measure in terms of light performance.

Other shapes do not have an official cut grade but are sometimes given an estimated equivalent evaluation based on similar criteria. An Excellent cut grading will have the best light performance, mainly influenced by the relationship of surface table and the depth of the diamond (neither too deep nor too shallow).

Although not formally identified within diamond reports by the GIA or IGI, a "hearts and arrows" or "super ideal" cut have become additional terms used to describe a superior excellent cut diamond.

This refers to the visual appearance in some round brilliant cut diamonds which, when viewed from above using a special magnifying optical tool, displays a series of eight near perfect arrows radiating out from the centre of the diamond table.

When viewed from below, a series of eight hearts can be seen.

We typically suggest opting for a cut grade of Excellent. Please note that the shape of a diamond is also often referred to as it's cut, but is not the same thing as the cut grading.


The carat weight of a diamond defines its overall mass.

The actual weight of a one carat diamond is approximately 0.20 grammes.

All other key variables of a diamond being constant, the larger the carat weight the more valuable the diamond.

Below one carat, the weight is alternatively expressed in points.

For example, twenty five points is the same as a quarter carat diamond.

One carat GIA certified diamond

Diamond price comparison graph by colour and clarity - Pobjoy Diamonds

When hand selecting your diamond we employ a unique 20/20 evaluation process.

Make sure your diamond meets the Pobjoy Standard.

Diamond proportions - Pobjoy Diamonds


Graph assumes similar clarity, colour and cut.

Notice that the value of a diamond increases in value exponentially the larger the carat weight.