The 4Cs of Diamonds

Diamonds are considered to be the most valuable gemstones in the world. Whilst the reasons for this are many, and some of them potentially controversial. What is undeniable is the public perception towards these extremely harden collection of carbon atoms: Which tends to be one, or a combination of awe, interest, and the desire to possess. The economic value of diamonds, in addition to the general air of scarcity that is associated with them, is based on a number of different factors. Whilst it is natural for someone to associate great value with a diamond, simply because it is one. Yet, as one goes deeper into the study of these precious stones, one learns that is more what determines the value, and hence cost that is associated with diamonds, besides its rarity. In the diamond and jewellery industry there has emerged a certain set of standards with which diamond quality is determined. A standard by which diamonds that enter the consumer space-for diamonds are also used for industrial purposes-are assessed and graded. So whenever one hears a certain diamond selling for hundreds or maybe even millions of dollars, understand that there is a framework of measure that underpins it. Here we will learn what that standard is: the 4Cs of diamonds. And will do this by looking at some of the key measures for assessing a diamond’s value.

What are the 4Cs of Diamonds?

The 4Cs of diamonds were introduced by the Gemological Institute of America (GIA), in collaboration with great diamond mining giant, De Beers with aim of determining a diamond’s market value. The 4Cs of diamonds is a vigorous way through which a diamond’s value is determined, for it measures characteristics of a diamond by assessing 4 key factors. They are:


First, when it comes to diamonds, one must understand that colour, in relation to its value, is viewed from the standpoint of its absence. So the less colour that is present (visible) in a diamond, or the apparent colourless character of the gemstone which determines its value. Leaving aside the particular category of this gemstone, known as coloured (fancy) diamonds. So diamonds proper, those that dominate the market for fine jewellery, are valued in accordance with the absence of colour. Which occurs at various degrees. For example, when one thinks of diamonds there is a tendency to associate them with the absence of colour, owing to their apparently transparent character. However, in reality, most (colourless) diamonds fall within a spectrum, with gemstone containing shades that run from the light yellow colour to or even light brown tones.

The D-Z Scale

The colour of diamonds is graded according to the D-Z scale. With diamonds that range from the letters, D-H is those that contain the lowest tone of yellow, which in turn contributes to their greater value. Within this, there is a D-F range, which is referred to as the “Colourless”. And is the most expensive variety. Diamonds that fall in the G-H range is the second tier of diamond colour value, and are referred to as “Near Colourless”. Unlike the D-H range, this group contains a small percentage of colour (yellow shade). However, the presence of this colour tone is negligible and can be offset by other factors, such as a good cut etc. The N-Z colour range of diamonds is generally of a lower value owing to the higher percentage of a shade of yellow. Since the higher the colour, the lower value of the diamond. However, those who are looking for a larger carat diamond may consider those that fall in this range.


OK. What is meant by the term carat? Carat is the unit of measure that is used to the physical weight of diamonds and other gemstones. To get some number out of the way: A carat equals 0.200 grams or 1/5 gram. Needless to say, the larger the carat the greater price of the diamond. In fact, this principle applies to virtually all gemstones. This is straightforward. Whenever one speaks of having a great diamond (engagement) ring, often the main talking point is the large centre stone. A larger carat diamond corresponds to a greater value, for in addition to the relative rarity of larger carat diamonds, the size of the gemstone can be employed as an offsetting factor in relation to other factors. For example, an engagement ring with a lower colour grade diamond (N-Z range), can be a worthwhile choice if it has a larger carat (2.0 – 5.0).


When it comes to the choice of fine jewellery, the cut of the diamond is arguably the most important factor. From a visual standpoint, the type of cut that the diamond is subjected to along with depending on the quality of the cut affects its visual appeal and ultimately its cost. The quality of cut of the diamond is measured by an expansive jargon of terms, that at a technical level is described by terms such as its proportions, the symmetry of its facets; the capacity of the cut elevates the diamond’s brilliance, its fire, and scintillation that combine to the quality of the diamond’s finish. The GIA grades the quality of a diamond cut on a scale: From Ideal, Excellent, Very Good, Good, Fair and Poor.

Cut + Shape of the Diamond

The cut of a diamond is affected by the specific shape of the diamond. Diamonds are popular diamond forms into which diamond are shaped, which elevate certain aspects of the gemstone. With certain diamond shapes being at the same time being able to minimize the other weakness that the gemstone may have. Hence the suitability of a specific diamond shape can be strengthened by a high-quality cut. The six most popular diamond shapes are Princess, Round, Emerald, Cushion, Oval and Pear. Followed by other interesting diamond shapes: Emerald, Radiant and Asscher. Note that each of these diamond shape names is usually followed by the word “cut”. However, the cut of a diamond differs as per the specific aims of the jeweller/buyer. For example, jewellers may opt between shallow, deep or ideal cuts. Whilst certain cuts may seem better than the other; however, each of these cuts is determined by other qualities of the gemstone in question. For sometimes less than ideal cut may be preferable if it helps accentuate other positive aspects of the diamond. Thus it is important to understand that simply because a diamond has an “Excellent” cut, it does not guarantee a high-quality diamond.


The clarity of the diamond determines the presence (or absence) of imperfections within the diamond, known as inclusions. Inclusions are naturally occurring blemishes within the gemstone, which are not unique to diamonds. The clarity of diamonds are rated from Flawless (FL) to Included (I). Flawless diamonds, along with Internally Flawless (IF) seem almost perfect to the naked eye. Whilst those that are graded as Very Very Slightly Included (VVS), owing to their virtually inclusion-free character, also score highly. As inclusions, the few, are very hard to spot. The word ‘stunning’ is often associated with these flawless to near flawless variety. A diamond that has a clarity level that falls into the Very Slightly Included range, are a step below, as the inclusions they carry can be viewed under 10x microscope, however the inclusions are extremely minute. In fact, the clarity of an Slightly Included (SI) diamond appears near perfectly when viewed with a naked eye, virtually the same as VVSI. The difference however, lies with the price. Jewelers often recommend going for a diamond with lower clarity (e.g. VSI) as a cost saving method, but will encourage you to go for a more popular cut. Sightly included are next in line. However, the presence of inclusions are only noticeable under magnification, and hence make a good diamond choice, when cut and polished well. Included (I) are generally not a popular choice.

Beyond 4Cs?

One must keep in mind that the 4Cs are alone not sufficient when determining the value of diamonds. Since beauty is in the eye of the beholder (most of the time), which means that the actual value of a diamond may not always correspond to the perceived value of the potential buyer. And given the sheer number of factors that affect the final quality of, not exactly the diamonds per se, but the jewellery item that one wishes to have. Unless one is in the market to buy quality diamonds-where a deeper knowledge of gemstones is needed-when it comes to diamond jewellery, like engagement rings, a more rounded understanding of the process of buying quality, but affordable diamond jewellery is needed. From the shape and size of the gemstone, the precious metal of choice, to the use of accent stones etc.