The 4 C’s

The 4C’s: The most important characteristics of the diamond

The 4C's are known as the most important characteristics of a diamond for which it is valued. They correspond to the initials of the following words: Cut, Color, Clarity and Carat Weight.

In the early commercial history of diamonds, there was no formal way to categorize them. They used terms such as:

  • “Water or river” when it was meant that the diamond was colorless or “Cape” when they had yellowish tones; associated this term with the Cape of Good Hope region of South Africa.

  • “Without defects or without imperfections” when it was wanted to mention that a diamond had a good purity.

  • “Well done or badly done” when it came to the quality of the carving.

It was not until the early 1940s when the GIA institute created the definition of the 4C’s in order to better communicate, both to customers and apprentices in the field, the most important classifications of a diamond to consider. Which we detail below:


It evaluates how proportionally cut a diamond is. The better the quality of the cut, the higher the shine it will give off. This is because there is an ideal ratio in which a stone should be carved so that the path of light within is the most beneficial. Let's look at the following image for a better interpretation:

As we can see, of the 3 types of cuts reflected in the image, only the ideal one allows the light to be released from above the stone, giving the diamond a great shine from the side where it is appreciated.

Cut scale:

It has the following classifications: Excellent, Very Good, Good, Fair and Poor.

The cut is the only characteristic of the 4Cs that is not determined by nature, but by humans. Before cutting a rough diamond -uncut diamond- the specialist must consider certain facts to define what to prioritize in the result: cut, color, weight (carat) and/or purity. Since depending on how a diamond is cut, it will influence its other characteristics.


Before the color scale as we know it today existed, some merchants used the letters A, AA and AAA as a way to classify them. Others made use of the Arabic numbers 0, 1, 2, 3. As well as some others of the Roman numerals I, II, III. Not only did these mechanisms lack international agreement, but they were also imprecise. It was in 1953 when the GIA institute created a scale used internationally to accurately categorize the color of a diamond, which we will find below:

The scale starts from the letter D to avoid confusion with previously used classifications that involved the letters A, B and C. It goes from D -being the most colorless and most valued grade- to Z -having more yellowish tones and decreasing its value-. After the Z, the scale of the Colored Diamonds  begins, which are categorized as exceptional pieces, increasing their value.


This classification analyzes the impurities -inclusions- and the imperfections or stains -blemishes- of a stone. When we talk about impurities, we mean internal flaws that were created in the diamond development process. Like an internal crystal with an appearance of a black dot. When we refer to blemishes, we are talking about defects in the surface of the stone, such as scratches or scratches.

Clarity scale:

  • Flawless (FL): It does not have inclusions (internal) or imperfections (external) visible with a 10x magnifying glass (10x gemological magnifying glass). It is the purest grade on this scale. They are almost impossible to find, so their value is extremely high.

  • Internally Flawless (IF): It does not have visible inclusions with a 10x magnifying glass, but some imperfections can be seen. Diamonds of this grade are very difficult to find, their price remains high.

  • Very, Very Slightly Included (VVS): Impurities are so slight to see even for an expert with a 10x magnifying glass. Although these stones are very pure, they are more common to find and their price -despite being high- is more accessible. This category is divided into VVS1 and VVS2, the former being purer than the latter.

  • Very Slightly Included (VS): You can carefully observe inclusions using a 10x magnifying glass. They are often widely used in jewelry stores due to their price-quality ratio. This category is composed of: VS1 and VS2.

  • Slighty Included (SI): Impurities are noticeable with a 10x magnifying glass. They are very commercial due to their value, especially when they are diamonds with sizes less than 0.20 ct.

  • Included (I): Inclusions are easy to see with a 10x magnifying glass and can sometimes be seen with the naked eye. They can affect its shine, transparency and durability. They are stones that will hardly be set in Highend Jewelry pieces, they are not diamonds desirable for consumers.

When choosing a diamond, we must consider that the larger it is, the more it will allow us to see inside it.


The measure of weight used for diamonds is called Carat and is usually abbreviated as follows: ct. One carat is equal to 100 points (another very common way to refer to the weight of a diamond), so 0.50 ct = 50 points. This last measure is widely used when we want to refer to diamonds weighing less than 1 ct; for stones with a higher weight, it will be used as carat measure.

If we compare this measure with another more common one, we can say that 1 carat is equivalent to 200 mg.

The larger a diamond is -comparing with stones of the same grade (cut, color and clarity), the greater its value. This is due to the scarcity and demand for the stones as their volume grows. There are also sizes of desire for consumers, which by having greater demand, increase their value. Some of these measures are: 0.50 ct and 1 ct; for being round numbers.

In the following image we can see some weights of diamonds with the dimensions that they could have if they were cut to an ideal size.

In conclusion, each of the 4Cs will determine the beauty, desire and value of a diamond. That is why we advise defining what are the aspects that we want to prioritize when choosing one. For not very demanding consumers who are interested in stones smaller than 30 points, we suggest prioritizing size and/or color and not purity, since inclusions in these sizes are difficult to perceive.