Types of Diamonds Explained: The Four Cs

Buying an engagement ring can be very confusing, the majority of people will only ever do this once and it isn’t something you would want to rush in to. Using just a few snippets of knowledge can get you a long way and help you to understand exactly what it is that you are paying for. There's a vast range to think about when it comes to the different types of diamonds available - with the four Cs being considered in almost every diamond ring purchase. But what exactly do the four Cs mean and how do they make each diamond ring different. In this guide, we'll delve into the types of diamonds and their cut, colour, clarity and carat.

What is ‘Carat Weight’ and why does it sometimes say approximately?

When measuring/weighing gemstones we use carat weight, just as when weighing yourself you would use kilogramsCarat refers to the weight and therefore the size of the diamond. One carat is divided into 100 points. Therefore, a diamond weighing 50 points is half a carat. Size is the most obvious factor in determining the value of a diamond.  But two diamonds of equal size can have very different values, depending on their cut, clarity and colour.

Sometimes if the diamond is already mounted then a gemologist will take a few measurements then use a complicated mathematical formula to estimate the weight. This gives you an approximate figure e.g. 1.00ct approx.


Image of a Diamond Ring

Why when describing diamond colour does it say a letter and not just a colour?

Diamonds come in a large variety of colours, the most popular being clear/white. Instead of using terms like very very white, very white and white gemmologists decided to use the alphabet as a scale. Colour grade ‘D’ is the best with each subsequent letter the colour is slightly worse. That said, to the untrained eye and without holding two diamonds side by side Colour ‘D’ all the way to ‘J’ could look the same in non-lab conditions. ‘K’ onwards you start to see a yellow tinge which becomes more and more prominent along the scale. The more desirable diamonds are graded ‘D’ to ‘I’ and therefore cost more.

Clarity, What is it and why do I need to know?

To make things clearer for consumers gemmologists have developed a way to describe if a diamond is as clear as day or as dull as a duck pond.

The scale is as follows:

Diagram of a Flawless Diamond

FL/IF = Flawless, To buy a flawless diamond you need to have very deep pockets. This is a stone with no visible imperfections. Just take into account the size of the diamond you are purchasing, would you really be able to see any flaws anyway if the diamond is only 0.15ct ? (I couldn’t!!)

Diagram of VVS1 VVS2 Diamond

VVS1/VVS2 = Very Very Small inclusions, for a stone to be graded VVS1/VVS2 a trained gemmologist must inspect a stone through an eyeglass for a number of minutes in order to see any imperfections such as a minuscule clear bubble. Will you be doing this? If not then it is likely you can purchase a lower clarity of diamond without knowing the difference.

Diagram of VS1 VS2 Diamond

VS1/VS2= Very Small inclusions, minute specs that may be visible to a trained professional when looking through an eye glass, the diamond could be perfect but for a couple of tiny specs of what look like dust inside the diamond. VS1/VS2 clarity diamond aren’t cheap, but they do look very good.

Diagram of SI1 SI2 Diamond

SI1/SI2 = Small Inclusions, This is where ‘normal’ people might start to see the inclusions, still with the aid of an eye glass but much easier to spot. SI1/SI2 clarity stones are more common and therefore you can get more bang for your buck.

P1/P2/P3 = These inclusion could be seen without the need of an eye glass. they could consist of what looks like grit in the stone or make the stone look cloudy. 


The Cut of a Diamond


Cut is the only diamond characteristic directly influenced by man – the other three are dictated by nature. A good round brilliant cut releases the life, fire and sparkle of a diamond through the arrangement and proportions of its 57 to 58 facets (tiny planes that create angles to reflect light).  When a diamond is cut the light will reflect from one facet to another and disperse through the top of the stone, resulting in a display of brilliance and fire. Diamonds that are cut to deep or shallow lose light that spills through the side or bottom.

Diagram of Different Diamond Cuts

The Shape of the diamond is a matter of personal taste, here are the most common:

  • Round Brilliant = The most popular.
  • Princess Cut = Square shaped
  • Emerald Cut = A rectangular shape
  • Pear Cut = Pear Shaped
  • Marquise = An oval with pointed ends.


Literally, thousands upon thousands of diamond cuts exist, just have a look on google, it’s bonkers. The better the cut the better the sparkle.