Diamond Education

The 4 Of Diamonds Guide: Carat, Cut, Color & Clarity

4Cs of Diamonds

Explanation of the Most Important Diamond Parameters: 4Cs Of Diamonds

They say real beauty is in the eye of the viewer. It is especially true when it comes to the individual assessment of one of nature’s most precious gifts – the beauty of a diamond, its brilliance, and sparkle. Although the selection of your diamond depends on your personal feelings and taste, it is objective quality criteria. In the following, we would like to bring you the basic knowledge. No two diamonds are alike. Each one is unique. It is why over the years a universal symbol for identifying diamonds has been set. The quality and value of a diamond are defined according to the 4cs of Diamonds: carat, color, clarity, and cut.

At Gemistone Jewelers, we are experts in analysing these characteristics. Our diamond grading reports cover all 4Cs of diamonds certification for loose diamonds; ensuring customers know accurately what diamond they are buying.

Die 4Cs Of Diamonds Quality

4cs of Diamonds: Carat (weight), Color (color), Clarity (purity), and Cut (cut quality). All of these properties determine the value of a diamond. A large diamond of poor quality can be worth less than a small but flawless diamond. It is therefore important to ensure that the diamond is of good to very good quality.

The First C: Carat (The Weight of Diamond)

Diamond Carat

The first C, Carat, is a measure of the weight of a diamond. This unit is also used to describe the weight of other gems. Historically, the name “carat” came from the Greek word “keration” translated as “fruit of the carob tree”.

The seeds of the carob trees were used in the Middle East, in ancient times, as a source for weighing gold and precious stones. Later, the carat (ct) was defined as 0.2 grams. Each carat is divisible into hundredths of a carat, called points. So, as an instance, a 1.35 ct diamond (one carat and thirty-five points) weighs 0.27 g. The weight of a diamond has an important influence on the price.

The Second C: The Color from A to Z

First, we distinguish between “white” diamonds and colored diamonds. The diamonds used for jewelry are usually “white” diamonds. White diamonds go from bright white to pale yellow. The amount of yellow, caused by nitrogen, determines the price. The more yellow the lower the price. A color scale is used to describe the diamond color. The color scale ranges from D (colorless) to M (light yellow). Depending on the lab, the colors behind M are rated as “fancy Yellow”.

Diamond Colors

Fancy Diamonds

Although the diamond is mostly found in its transparent form, it is extremely rare in flawless white. Unpolished diamonds are also yellow. So-called “fancy diamonds” or colored diamonds are just as rare as bright white diamonds. They have tints outside of the colors D to Z and come in all color nuances – in red, orange, yellow, green, blue, purple, brown, gray, and black.

Higher Color or Higher Purity

For the observer, the higher tier color in the diamond rating is crucial. Even with an untrained eye, he can, for example, distinguish between a D and a G color. The purity of a diamond, on the other hand, can only be seen with a magnifying glass ten times magnification. This is the only way to determine inclusions and other purity features.

One aspect that influences color is fluorescence. This represents a diamond’s ability to transform UV light into visible light. The number of fluorescence is defined as nil, faint, medium, strong, and very strong. The exact syntax depends on the labs. Depending on the amount and color of the fluorescence, the diamond will appear whiter.

This appears when the conversion of the UV light results in blue light, a complementary color of yellow. In some cases, the amount of fluorescence is so high that the diamond appears “milky white”. This effect is only observed with very strong fluorescence. The degree of fluorescence changes the price discount to compensate for an overestimation of the color.

The Third C: Clarity (The Degree of Purity)

The clarity indicates the internal flaws present in a diamond. Purity is assessed using a 10x loupe. The evaluators use a higher magnification stereo microscope in the labs, but the final decision is checked with a 10x magnifying glass.

Diamonds Clarity at Gemistone

Purity depends on:

  • Size
  • The larger size of a characteristic impurity then lowers the degree of purity.
  • The number
  • The more visible internal defects, the lower the purity level.
  • The location
  • If inclusion is located near the table or collect, the rating is stricter than if it is located near the girdle. If the position of inclusion leads to multiple reflections, all reflections are included in the purity assessment.


In some labs, a distinction is made between internal and external characteristics. In the third Antwerp grading lab,” all external characteristics are listed under “Polish grade”, part of the “Cut grade”. This means that any defect due to the operation will not be reflected in the purity. Other labs can display both internal and external characteristics in the purity grade.

A purity scale has been developed to present the purity rating. All grading labs have their purity scale and designations. As an example, we give the two most commonly used scales, used by labs that work according to the standards of the International Diamond Council (IDC) and GIA.

The Fourth C: Cut (The Cut of Diamond)

The fourth C, the cut, describes the diamond’s shape and proportions. The proportions of a particular shape, usually the brilliant shape, affect the diamond’s optical performance. Let’s start with a rule of thumb that applies to all cuts, illustrated in the following photos.

Diamond Cut, 4cs of diamonds

One of the main purposes of the cut is to collect the incoming light and send it back to the observer. If the diamond is too shallow, it returns light next to the observers’ heads. It creates a “see through” effect and the glare is low.

In a normal form, the incoming light in the diamond mainly returns through the table, to the head of the observer. The diamond looks clear and the brilliance is optimal. If the diamond is too steep, the light will flow out of the stone through the pavilion. The observer sees the diamond as dark and dead (low brilliance).

Of course, there is a wide range of models and proportions. In addition to common optical parameters such as brilliance, fire, and scintillation, there is also a geographical and cultural difference. In Europe, HRD Antwerp was the first to develop a full rating system for the brilliant cut.

The dimensions were divides into groups called “Very good”, “Good” and “Unusual”. In addition to the proportions, she introduced a finishing grade (“finish grade”). This degree of finish was a mixture of evaluations regarding symmetry, finish, and negative optical effects.

Ideal Cut

The “ideal” proportions, the “Ideal Cut”. Special attention was given to the combination of table size and overall height. This was sufficient to remove diamonds that are too flat and too steep.

All other large laboratories have a system comparable to that of GIA or HRD Antwerp. The GIA system can best be describes as an individual assessment of the proportions of a diamond; the HRD Antwerp system is based on areas of proportion. The assessment, based on the proportions per diamond has the advantage that the irregularly shaped proportion areas give a better match with the optical performance. It is more difficult for manufacturers to predict the result during grinding. Systems with linearly bounded ranges of proportions are not as accurate near the bounds. The current research focuses on “fancy shapes”.

Diamond Cuts

First, there is differentiation in the forms. Some cuts have a lot of sparkles, fire, and scintillation (Brilliant, Flanders brilliant, Princess…) others are less sparkly and show more stylish geometric patterns (Emerald, Baguette…). The appearance of the well-known brilliant cut is often used as a references for existing and new cuts.

Historically, WTOCD has supported several new cuts. WTOCD was a co-designer of Flanders Brilliant and providing technical and legal advice to many diamond designers. In recent years, it has become clear to the diamond community that new cuts are a tool to boost their sales. The brilliant shape is an over-defined commodity item that makes branding very difficult. In the coming years, we expect a lot of new fancy shapes on the market. Let’s hope the claims they make are real and breathtaking…

The Agony of Choice

The 4Cs of diamonds make it clear: no gemstone is the same as another. That makes every diamond ring something very special. A wedding ring with a diamond stone is therefore something special anyway, regardless of the 4Cs of Diamonds: Cut, Clarity, Color, and Carat. There is a suitable ring for every taste and every budget. Because one thing is especially important: It has to please the bride and groom and put a smile on their faces.

Summary: 4Cs Of Diamonds

The 4cs of diamonds are the most important criteria for choosing a diamond.

With the prerequisite that diamonds with good values are really beautiful and with your knowledge, you can better decide which criteria you want to value.

As a specialist, we need to provide you with the best possible support in choosing the diamond of your choice. That is why Gemistone Jewelers offers you additional information on all diamonds. These details enable you to find the stone that meets your very personal needs and to buy it at Gemistone Jeweler’s shop without seeing it beforehand.

At Gemistone, the fulfillment of a high level of customer satisfaction is an essential four point. After all, diamond jewelry from Gemistone fulfills the most demanding requirements in terms of quality and design.

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