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The “4Cs”: how to choose the right diamond?

The “4Cs”: how to choose the right diamond?

Worried about paying the right price? Are you struggling to sort through the multitude of possible choices? Ask one of our jewelry experts for advice here.

Our recommendation in a few words:

Each of the 4Cs - Cut (size), Color (color), Clarity (purity) and Carat (weight) - play some role in the beauty of the diamond, although it is complicated to consider each component in isolation. The 4Cs interact with each other to form a whole, creating a unique alchemy. In general, we recommend to favor the quality of the cut, which makes the diamond beautiful and which will maximize its brilliance. It will then be a question of finding the right balance between the color and the level of purity according to your budget. If you need help assessing a diamond's quality and price, please feel free to contact our experts right now.

What are the “4Cs” of a diamond?

The 4C classification was created in 1976 by Martin Rapaport to assess the price of a diamond. A classification reserved for international professionals.

The 4Cs represent the four main characteristics of a diamond's beauty and shape: Cut (size), Color (color), Clarity (purity) and Carat (weight). When looking at a diamond, the eye perceives these four components in particular without necessarily being able to distinguish them.

Each C is evaluated according to a certain scale which will allow its quality to be determined. Even if certain terminologies and grading standards exist, these assessments may differ depending on the laboratory. The most famous laboratories are the GIA (Gemological Institute of America) and the HRD Antwerp. For any purchase of a diamond of 1 carat or more, we recommend that you request a certificate from the seller.

The 4C rating helps determine the value of a diamond and gives a good indication of its quality. Generally speaking, diamond dealers set their prices on the basis of these gradation ratios. As a buyer, it is important to understand the basics of this valuation system knowing that in the end, the most important thing is the appearance of the diamond, as seen with the naked eye. So, in our opinion, it's best to avoid spending your entire budget on a feature that will ultimately be invisible to the naked eye. We recommend going towards a fair balance of 4Cs, so as not to overpay one of the Cs and conversely, underpay another.


The cut specifically refers to the quality of the angles of the diamond, its proportions, the symmetry of its facets, its brilliance, its sparkle and its finishing details. These factors have a direct impact on the brilliance of the diamond as well as on its aesthetic appeal in general. The GIA classifies the different levels of pruning quality into six categories: ideal (ideal), excellent (excellent), very good (very good), good (good), correct (fair), and mediocre (poor). The ratings “ideal” and “excellent” mean that the proportions and size of the angles allow for maximum shine and sparkle.


Sizes can vary significantly depending on the diamond and diamond cutters. Depending on the demands and the objectives of the moment, a cutter can choose to maximize the number of carats, which can lead him to realize a diamond too deep or on the contrary, not enough, not allowing an optimal reflection of the light. In other situations, the diamond is cut to minimize the number of inclusions in order to improve its purity at the expense of its brilliance.

In any case, we believe that it is essential to pay particular attention to the quality of the cut when choosing a diamond. The latter is the most important indicator of a diamond's beauty, and should therefore be prioritized over other “C” s. Finally, you must be aware that even for sizes noted as being of very good quality (such as excellent for example), the diamond in question can be really exceptional or else relatively mediocre in the end. Thus, we always recommend to seek the advice of an expert.


The color of the diamond is expressed in gradation of white or no color. GIA ratings range from D to Z, with D being completely colorless and Z having a marked yellow / brown tint.

The price of the diamond will reflect this rating which can significantly affect its value. In most cases, the naked eye cannot distinguish two adjacent colors, but the price difference can be large.

Regarding Color, the key is to determine if the diamond appears colorless in its setting. It is also important to make sure that the diamond does not have a tint that interferes with reflections of white light and color.

Note, some colored diamonds have real value, such as pink or green "fancy" diamonds which are particularly sought after. The rating scale of their colors varies from those of traditional white diamonds.


Purity assesses defects in the diamond which may have surface imperfections and internal inclusions. The GIA has established the following rating scale:

  • FL (Flawless): no fault
  • IF (Internally and externally Flawless): No internal defect visible with a magnifying glass magnifying 10 times
  • VVS1 & VVS2 (Very, Very Slightly Included): Tiny inclusions barely perceptible with a magnifying glass magnifying 10 times
  • VS1 & VS2 (Very Slightly Included): Very small inclusions detectable with a magnifying glass by a
  • SI1 & SI2 (Slightly Included): Small inclusions visible with a magnifying glass
  • I1 & I2 (Inclusions): inclusions easily visible to the naked eye

Depending on the size, positioning and darkness of the spots (black spots commonly called "toads") and inclusions, these imperfections can interfere with the light passing through the diamond. When this is the case, the brilliance and beauty of the diamond suffers, diminishing the benefits of high quality cutting.

We recommend to make sure that the diamond does not have any defects visible to the naked eye and that the inclusions do not interfere with the reflection of the light.


Many people think that the number of carats refers to the dimension of the diamond, but in reality it is simply its weight. 1 carat weighs 0,20 grams. Depending on their shape and how they are cut, two 1 carat diamonds can each have quite a different dimension.

Some people will favor the cut of the diamond, while others the transparency (clarity).

How do the “4Cs” interact with each other?

Each of the 4Cs contributes to the overall beauty of the diamond and makes each stone unique. A diamond must be considered as an organic whole because the eye has difficulty in differentiating each component (the 4Cs). Thus, we must understand how the 4Cs interact with each other.

What is the most important C?

It depends on your expectations, each person will give more or less importance to each C according to their own tastes. However, we present our opinion below, which is our sole opinion:

  • La Size (Cut) : this is the element that has the most immediate and direct impact on the beauty of a diamond. Look for diamonds with a high brilliance and exceptional lights while being ready to cut your budget on other criteria, such as Purity or Color.
  • La Color : the second most important aspect. A diamond should appear white or colorless to the naked eye. Make sure that the Color does not interfere with the refraction of white light.
  • La Purity (Clarity) : third item on the list. Choose a diamond that does not show any flaw to the naked eye. Spots and inclusions must not reduce the brilliance of the diamond.
  • Le Weight (Carat) : last criterion in the choice of a diamond but which remains important. Think about the number of carats you want ideally, but don't hesitate to reduce the weight to be sure to maximize the brilliance and beauty of the diamond.

Feel free to contact our experts to make sure you buy an exceptional diamond that fits your budget.

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