The 4 Cs of Diamonds Explained – Become A Diamond Expert

The 4 Cs of Diamonds - cut, colour, clarity and carat weight

Selecting a gorgeous diamond involves more than meets the eye; there’s an entire science to it.

While you might know about carat, a diamond’s true value isn’t just about its weight. It’s a combination of deciding factors that collectively contribute to its beauty and rarity, otherwise known as the “4 Cs”.

Let’s briefly look at this grading system and how you can choose the best brilliant diamond.

What are the 4 Cs of Diamonds?

The 4 Cs – cut, colour, clarity and carat weight – serve as the universally acknowledged benchmarks for evaluating a diamond’s quality. These characteristics are like a diamond’s unique fingerprint, influencing its sparkle, appearance, and value.

Who Came Up with the Concept of the 4 Cs of Diamonds?

To understand how the concept of the 4 Cs of diamonds came about, we need to look at the gem trade before the 1940s. Going as far back as the 1500s, merchants and jewellers used a hodgepodge of inconsistent terms to describe diamonds and what made them valuable.

Cut was often “made well” or “made poorly”, colour was “tincture” or “tint,” and clarity was “without flaws” or “with imperfections”. The only constant was the term “carat” to signify weight. This mix of words made it difficult to explain the value of diamonds to customers and for customers to remember these critical aspects.

It wasn’t until the early 1940s that the concept of the 4 Cs was born, courtesy of Robert M. Shipley. Shipley, a former retail jeweller, founded the Gemological Institute of America and introduced the 4 Cs as a mnemonic device to simplify diamond evaluation.

A woman wearing diamond pendant earings, a diamond bracelet with gemstones in rainbow colours and a diamond tennis necklace.

Can You Tell if a Diamond is Good Quality with the Help of the 4 Cs of Diamonds?

The value of a diamond hinges on several factors, and rarity is one of the major contributors. The quality of a diamond can be defined by the combined factors – cut, clarity, colour and carat.

  1. Diamond cut: A diamond’s cut dictates the diamond’s ability to reflect and capture light. Looking at balance, brilliance, and dimensions, a diamond’s ‘Cut’ is graded as “Excellent,” “Very Good,” “Good,” “Fair” and “Poor”.
  2. Diamond colour: ‘Colour’ evaluates the absence of colour and grades diamonds from D (colourless) to Z (light yellow or brown). The closer to D, the more valuable the diamond.
  3. Diamond clarity: Fewer inclusions or imperfections generally result in a more valuable diamond. This chart assigns a clarity grade, ranging from Flawless to Included.
  4. Diamond carat weight: One carat equals 200 milligrams, split into 100 “points” for a precise measurement. Natural diamonds can lose up to two-thirds of their total carat weight during cutting and polishing.

What is the most important of the 4 Cs of diamonds?

Cut impacts the diamond’s beauty the most. A poorly cut diamond can’t be saved by its clarity, colour, or carat; it will appear dull and glassy. A well-cut diamond will capture and reflect light beautifully, creating that signature sparkle.

What is better, clarity or carat?

In most cases, clarity is considered more important than carat, particularly when choosing a larger diamond. As the carat weight increases, clarity becomes even more crucial because flaws are easier to spot in larger diamonds.

What’s more important, colour or clarity?

The importance of colour versus clarity most often depends on the diamond shape – not to be confused with cut. For instance, clarity holds more importance for shapes like Emerald, Princess, and Asscher, while colour matters more for Cushion, Radiant, Pear, and Oval shapes.

What is the least important of the 4 Cs?

Carat is typically considered the least important. This is because carat refers to the weight, not the size of the diamond. Even when two diamonds have the same carat weight, the cut and shape will affect how large the diamond appears.

How To Use the 4 Cs of Diamonds When Buying Fine Jewellery

The 4 Cs offer you the know-how for selecting the perfect diamond-adorned piece of fine jewellery. Here’s how you can apply this knowledge to your advantage:

  • Prioritise an ideal or round brilliant diamond cut, especially for rings, even if it means choosing a lower-weight diamond. You can compromise slightly on colour and clarity to stay within your budget.
  • Clarity becomes crucial in close-up jewellery pieces like bracelets and earrings.
  • For fine jewellery, such as necklaces, you have more flexibility in terms of diamond colour.

Searching for the perfect piece of jewellery, especially when it’s an engagement ring, can feel overwhelming. But with this knowledge, your fiancee’s delighted declaration of “Look at my stunning diamond engagement ring!” becomes within reach.


While the 4 Cs serve as invaluable tools to invest in a quality diamond, remember that they are just the beginning. Ultimately, the true measure of a diamond’s worth lies in its visual appeal.

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