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What are the 4 C’s of diamonds? This is Your Ultimate Guide

Posted by Burrells on Sep 20, 2018 1:36:26 PM


Buying a diamond is unlike any other purchase. Not only are you making a big financial investment but often a big emotional one. Diamonds are bought as gifts for someone with great importance in our lives or commonly as the centrepiece of an engagement ring.


Tell me a little bit about diamonds

Diamonds have a prestige and significance in our culture that makes them hugely meaningful. So, this is not an occasion where you want to walk into a shop and buy the first shimmering stone that catches your eye.

This is a time for careful consideration and expert guidance. Diamonds truly are forever and this means they deserve a little extra work on the buyer’s end.

Here at Burrells, we have over 40 years of diamond expertise, and we advise all our clients to spend time getting to know diamonds better before they set about looking at stones or jewellery.

collection of diamonds

The information surrounding diamonds may seem overwhelming at first, but the truth is, in just a few hours, you can get to grips with the key aspects of this most precious of stones.

One area where it’s worth focusing your attention is the 4 C's. Each of the 4 C's describes a different aspect of what makes a diamond unique and combined, they impact the beauty, desirability and, importantly, the price tag of a diamond.

Today, we are going to look at what the 4 C's mean in relation to diamonds and the measures that can help you understand where a diamond sits within the scale.



Before we dive into the 4 C's it is useful to understand the silent ‘C’ that often stands behind them. Certification. The two major diamond certification agencies are the GIA (Gemological Institute of America) and the IGI (International Gemological Institute).

We will look at GIA grading scales below. We recommend that you buy certified diamonds where possible – this will enable you to feel confident in the quality of the stone you are purchasing. Although it’s worth noting that certified stones will attract a higher price tag.  


What are the 4 C's?

Ok, so let’s jump into the 4 C's. First of all, what do the 4 C's stand for?

  1. Cut
  1. Colour
  1. Clarity
  1. Carat (weight)

These are the four defining characteristics of any diamond and the four elements that you should be thinking about before making a purchase. We look at these components in more details, below.


The 4 C's Explained



Cut is often held up as the single most important of the 4 C's. This is because it can have a dramatic effect on even the most beautiful raw stone. Cut can effect many aspects of a diamond, including its proportions, angles, symmetry, brilliance, fire and polish.

round brilliant cut diamond

A poor cut can create a dull, lifeless stone that lacks the personality of a truly dazzling stone.

It’s important to distinguish diamond cut from diamond shape. The latter refers to the overall shape of the diamond as opposed to the quality of the cut itself.

A professional cutter must balance the most optimal cut (maximum brilliance and fire) against the yield from a rough stone, keeping the maximum carat intact.

Many buyers are keen to obtain the maximum carat for their budget, but this can sometimes mean sacrificing the quality of the cutWe recommend buyers place quality of cut at the top of their list when shopping for a diamond and, where possible, obtain expert advice on cut from a professional jeweller.


How is Cut Measured?

The GIA uses a grading of Excellent, Very Good, Good, Fair, and Poor. The excellent cut grade is used to signify diamonds with exceptional brilliance and fire.

Beware of sellers that substitute their own grading scale for diamonds – they often assign lower quality diamonds a higher ranking than they would receive from the GIA.




For white diamonds, the optimum result is a colourless diamond. This is a diamond that has no yellow or brown tinges. The exception to this is sought after coloured diamonds, like pink or green diamonds.

looking at a pink diamond

For white diamonds, colourless stones are highly prized because they offer a higher reflection of light than diamonds that have faint, yellowish or brown tinges.

When assessing the colour of a diamond and its certification, it’s important to remember that diamonds are tested in a specialist viewing environment, designed to highlight even a very small amount of colour.

Under normal light conditions, faint amounts of colour may not be visible, and colour can be subdued by a high-quality cut. Colour may, however, be more noticeable in larger stones. 


How is Colour Measured?

The GIA uses a scale of letters to measure colour, between D to Z, with D being colourless and Z containing a noticeable tint. The differences between grades D to F can rarely be discerned with the naked eye.





Diamonds are formed under immense heat and pressure deep under the ground. As a naturally occurring material, they sometimes contain small flaws. These flaws or blemishes are called inclusions.

diamond clarity

Generally, the most sought-after and highest-priced diamonds are those that contain few or no inclusions. These are called ‘flawless’ diamonds. The presence of inclusions can interfere with the way light travels through a diamond, rendering them less brilliant.

It’s important to look closely at a diamond to determine it is ‘eye clean’ which means it contains very minor or no visible inclusions.

The cut of a diamond and the setting can also be used to mask any visible inclusions. Diamond cutters often prepare stones so that inclusions will be hidden by the bezel or claws of a setting.

You may need to obtain a professional opinion from a jeweller to confirm if inclusions are present and if they are likely to interfere with light refraction.


How is Clarity Measured?

The GIA use the below clarity scale to grade diamonds:

  • Flawless (FL):
    No inclusions or blemishes are visible to a skilled grader using 10× magnification

  • Internally Flawless (IF):
    No inclusions and only blemishes are visible to a skilled grader using 10× magnification

  • Very, Very Slightly Included (VVS1 and VVS2):
    Inclusions are difficult for a skilled grader to see under 10× magnification

  • Very Slightly Included (VS1 and VS2):
    Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification

  • Slightly Included (SI1 and SI2):
    Inclusions are noticeable to a skilled grader under 10x magnification

  • Included (I1, I2, and I3):
    Inclusions are obvious under 10× magnification and may affect transparency and brilliance

Any diamond graded at VVS2 and above has no inclusions, or those that are not visible to the naked eye. It should be noted that flawless diamonds are exceptionally rare, with only 1 in 5000 stones being classified as such.





Often buyers equate carat with size but, in fact, carat describes the weight of a diamond. A carat weighs exactly 0.2 grams, which is about the weight of a single paper clip.

looking at a diamond carat

The word carat is actually derived from carob, a type of seed that was traditionally used as a measure of diamond weight. Carat should not be confused with karat, the unit of measurement for gold purity.

The larger the diamond, the rarer it is, so it follows that higher carats will demand a higher price.

Savvy buyers should not equate size with quality. A slightly smaller but better-cut diamond is much more pleasing to the eye than a large but poor-quality stone. 

If you want to find out more about this, have a read of our blog post: Is a Bigger Diamond Always Better? Here’s What You Need to Know


How is Carat Measured?

Carat is a unit of weight equivalent to 200 milligrams. The size of the diamond may not always be an indicator of how heavy it is, two individually cut and shaped 1 carat diamonds can look very different.


Diamond carat sizes on a real hand

Photo credit: www.erstwhilejewelry.com


How Do I Choose the Perfect Diamond?

The 4 C's are a useful starting point for assessing and comparing diamonds but ultimately it is a very personal choice. Understanding your priorities and preferences in reference to the 4 C's can, though, narrow your search and help you to make smarter buying decisions.

Pop into a friendly Burrells store today to learn more about diamonds and perhaps discover the diamond you have been searching for. If you have any questions, our diamond experts are always on hand to help. You can get in touch here

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