The 4 C’s of Diamonds

Thanks to a masterpiece of marketing and advertising by DeBeers in 1947 where it was declared worldwide that “A diamond is forever”, diamonds are now the most popular choice for engagement rings and other jewellery. However, until the middle of the twentieth century, there was no agreed-upon standard by which diamonds could be judged. The Gemological Institute of America (GIA) created the first, and now globally accepted standard for describing diamonds: Colour, Clarity, Cut and Carat Weight. Today, the 4C’s of Diamond grading is the universal method for assessing the quality of any diamond, anywhere in the world.

Before you shop for that show-stopping diamond, let us help you to understand the Four C’s of Diamonds.  Every single diamond, like a snowflake, is unique.


A diamond’s cut grade is an objective measure of a diamond’s light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond (which gemmologists refer to as the table). If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.

Of the 4C’s, cut is the most important characteristic because it has the greatest influence on a diamond’s sparkle. Simply put, the better the cut grade, the more it will sparkle. Even if a diamond has a perfect clarity and colour grade, if it has a poor cut, it may appear dull.  We recommend choosing the highest cut grade within your budget. Very Good or better, if possible.


Colour is the second most important characteristic because the human eye detects sparkle first (diamond cut) and colour second.  As a diamond’s colour grade improves, its price increases. However, at a certain point, the colour difference cannot be detected unless under professional magnification. To maximise your budget, choose what’s called a near-colourless diamond (grades G-H) because the naked eye will still not see traces of colour for these grades.


The third most important characteristic of a Diamond is Clarity.  Clarity refers to the tiny natural imperfections that are present in all but the rarest diamonds, these imperfections are known as inclusions. Diamonds with the least and smallest inclusions receive the highest clarity grades.  You may want to consider an SI quality diamond, knowing that it may have very slight inclusions visible to the naked eye.

Because these imperfections tend to be microscopic, they do not generally affect a diamond’s beauty in any discernible way.

Carat Weight

The most well-known and misunderstood characteristic of the 4C’s is Carat Weight. It actually refers to the diamond’s weight, not its size. A diamond’s cut impacts how large the Carat Weight will appear.

To maximise your budget, consider buying a diamond that is slightly below your ideal carat weight. For example, instead of a 3.0 carat diamond consider buying a 2.9 carat weight.  Keep in mind, diamond prices increase exponentially with carat weight because the larger the carat, the more rare the diamond.

For many the purchase of an engagement ring is the first time that they buy a diamond. If we are privileged to supply yours we hope that you will then be back to see us again and again. Our commitment is to you and your jewellery.

If you would like an appointment, then please do call for a free consultation in our Berkhamsted Office or if you require a home visit we would be delighted to come and visit you.