If you aren't familiar with these gradings and what they signify, this can be confusing. They are there for good reason though; the four Cs are a globally accepted standard by which the diamond industry evaluates the quality of a given stone. Today we're taking a closer look at them and what they mean.
Each C represents a key characteristic (cut, colour, clarity and carat weight) which is graded in order to assess the diamond's calibre. The GIA (Gemological Institute of America), a prominent organisation in diamond evaluation, are responsible for most of the grades used. In turn, these gradings establish the retail value of the stone, with higher quality stones commanding a higher price.
Understanding the four Cs can help you to better understand what you are buying as well as helping jewellers to communicate their products and pricing. Consideration of the four Cs can also help you to weigh up any trade-offs you are willing to make in the pursuit of your perfect diamond!
The four Cs
Cut
The cut of a diamond refers to the factors that create the sparkle; its brilliance, facets (surfaces), angles, proportions, finish and more. Together, these elements create the overall look of the diamond; they determine how much light the stone reflects and therefore how well it sparkles.
The grades for diamond cut are Ideal, Excellent, Very Good, Good, Fair and Poor, with Ideal cut giving the most sparkle and Poor the least - and the price for diamonds graded in these categories will correspond with their grade. Ideal, Excellent and Very Good graded cuts tend to be good choices for engagement rings, depending on how the stone is set and how the cut interacts with the other Cs.
Colour
While we use the word colour, this is actually a measure of how colourless the diamond is. The colour is graded using letters; the GIA grades are D to Z, with D being the most colourless, and Z being a noticeable brown or yellow. There are of course many shades in between, and generally these are grouped into a colourless range (grades D-F), near colourless (grades G-J), faint (K-M), very light (N-R), and light (S-Z).
The colour grading has an impact on the price of the diamond, with the letters further down the alphabet costing less; Z would be the cheapest colour grading.
Most of the diamonds used in engagement rings will be in the colourless or near colourless range, with the letters next to each other being very similar in colour. For example, on the colour grading chart, a diamond with the colour F has been graded as higher than one with the colour G and will be more expensive. However, there is a school of thought that the best value comes from diamonds graded G, H and I, since their colour is near-colourless, their price is often lower, and to many people, the colour difference is unnoticeable.
Coloured diamonds, or 'fancy diamonds', such as pink or blue ones, are excluded from this grading, which is just used for classic 'white' diamonds.
Clarity
The clarity of a diamond refers to its 'cleanness', defined as the presence of blemishes or inclusions. Inclusions are small imperfections which occur naturally as the diamond forms. This can be the presence of minerals or crystals which become trapped inside, or hazy-looking spots.
It is very unusual for a diamond to have no blemishes or inclusions at all, but most of them can only be seen when magnified. The clarity grading chart rates diamonds based on the presence of these inclusions and how visible they are.
The grading scale for clarity can be difficult to understand, as it combines both letters and numbers. The chart goes from FL (flawless) to I1 and I2 (Inclusions). Other gradings include VVS1 and VVS2 (Very very slightly included), VS1 and VS2 (Very slightly included) and SI1 and SI2 (Slightly included).
The numbers reflect separate gradings within each category, with 1 being 'above' 2. For example, VS1 would be judged as 'better' than VS2 in terms of the grading system.
However, when considering which clarity is best for you, it's worth noting that the vast majority of imperfections are not visible to the naked eye. While FL is technically the best clarity money can buy, many diamonds in the other grades are eye-clean; 99% of VVS1 and VVS2 graded diamonds and 95% of VS1 graded diamonds appear entirely eye-clean, for example.
Carat
Carat refers to the weight of the diamond. Importantly, this is not necessarily the size of the stone; it is perfectly possible to have two diamonds of the same carat weighting that look different in terms of size.
A metric carat is 0.2 grams, with one carat being divided into 100 points. Their carat weight is rounded to the nearest decimal place, leaving you with a numerical figure that has been rounded to the nearest 'point', for example 1.24.
Carat is typically the most objective of the four Cs, since it simply requires a highly accurate scale that is capable of measuring very small weights.
Which of the diamond Cs is the most important?
It's important when considering which C is most important to note that none of them exist independently of each other; each factor interacts with the others in different ways, so it is difficult to claim one as the singular important factor.
However, it is broadly thought that the most important of the four Cs is cut, since it is the determining factor in the diamond's overall brilliance and sparkle; a poorly cut diamond could have exemplary colour and clarity but will still result in a diminished shine, ruining the overall look, whereas a well-cut one will bring out the other elements.
That's not to say that cut has to be the most important factor in your own choice - it's important that you choose a stone based on your own personal preference, which may be its size, shape, colour or another attribute.
Which of the diamond Cs is the least important?
There are multiple different answers and reasonings for which of the four Cs is the least important when buying a diamond. Some say that carat is the least important, owing to the fact that the weight does not necessarily reflect the size; for example, two stones with the same carat weighting can look hugely different depending on their shape.
Others believe that clarity is least important, since inclusions within diamonds can be incredibly difficult to see without specialist equipment or magnification, meaning that even a modest clarity grading can mean your chosen stone is entirely clean to the human eye.
Ultimately, it is for you to decide which elements matter least to you, or whether it feels important to you to opt for something that is graded highly in every element.
Is there a 5th C in diamond grading?
You may hear it said that there is a fifth C where diamonds are concerned - although considering that different sources have different suggestions for what this should be, perhaps it should be six! The most commonly stated fifth Cs are:
Certification or Certificate: The certificate is your promise that the grading of the four Cs for your chosen diamond is accurate as stated by the jeweller. This is often advised to be a grading report from an independent laboratory, to confirm the quality and value.
Conflict-free: Shoppers are becoming increasingly conscious that their diamond does not originate from countries impacted by civil wars where profits are often used to fund violent activities. Diamonds that are sourced in this type of environment are often known as blood diamonds.
Blood diamonds cause unspeakable damage to those involved, but it's worth noting that conflict alone is not the only ethical consideration. Even conflict-free diamonds can be extremely damaging to people and the planet, since mined diamonds can involve extreme working conditions that harm workers, and the mines themselves are detrimental to the environment surrounding them.
We'd prefer that the fifth C was not a C at all, and was instead an L: Lab grown.
For those seeking the most ethical diamond option they can, lab grown diamonds are made in safe and controlled laboratory environments with employment regulations and fair pay for workers. They also have fewer consequences for the environment - and they can match any mined diamond in each of the four Cs! If the ethics of your stone are important to you, it is worth researching the advantages of buying a lab grown diamond rather than looking only for conflict-free options.
Ready to browse beautiful, high quality diamond jewellery pieces that are also ethically and sustainably created? Take a look at our ethical engagement rings and other ethical diamond jewellery today, or get in touch if we can help with a bespoke piece.
