The 4C’s Of Diamonds: Diamond Quality Guide [2021]

4c's of diamonds

Until the mid of the twentieth century, there were no standard parameters to assess the quality of diamonds. During the decade of 1940, GIA gave new standards to the diamond that have been accepted globally as 4Cs. These 4Cs are Color, Clarity, Cut, and Carat Weight.

The 4C’s of Diamonds is a standard method to measure the quality of diamonds all over the world. These 4Cs have contributed to two major aspects of diamond sales and purchase:

  1. The Diamond quality can now be understood in a universal language
  2. Customers could know the quality of diamond they are buying

Now, several questions cross our minds regarding the GIA, 4Cs, and the quality of diamond:

What is GIA? What exactly are these 4Cs? How can these 4Cs be graded? How does the GIA grading report help you to buy an assured quality diamond? and Why GIA reports are necessary?

You won’t need to wait for any more to know the answers to all these questions. In this article, we are going to discuss all aspects of 4Cs. But before we elaborate further on 4Cs, we will talk a little about GIA, the creator of 4Cs Diamond Quality.

What is the GIA?

GIA is short for Gemological Institute of America. It is an institute that helps to understand the gem and its characteristics. GIA is one of the major sources of knowledge about diamonds. Its grading report is universally accepted as the final report to ascertain the quality of a diamond.

GIA’s main objective was to protect the diamond buyers from fraud and cheating which was quite prevalent in those days. They took it as a mission and the whole institute works towards achieving the objective. 4Cs of Diamond Quality and International Diamond Grading System is a result of ultimate passion and untiring perseverance exhibited by the team GIA. These new systems and methods are now considered as the universal benchmarks to evaluate the quality of Diamond.

GIA Grading

GIA is the first international institution to establish an International Diamond Grading System. Before GIA established the 4Cs and created the International Diamond Grading System, there were no standardized measures to evaluate the quality of diamonds. The decade beginning in 1940 revolutionized the diamond quality and grading systems. GIA created international standards to purchase and sell the diamonds. There were 3 major tasks carried out by GIA which included:

  • Created international quality standards for diamonds and provided a benchmark for diamond throughout the world
  • Prepared and established the best diamonds grading practices
  • Started issuing GIA Diamond Grading Reports to communicate precise information about the quality of diamond to the customers.

Today diamond grading reports created by GIA are not only universally accepted but also recognized as an original source of diamond grading. GIA Diamond Grading report provides all the information about the diamond shape, color, carat weight, cut, and clarity.

The GIA Diamond Dossier is a more precise version of the GIA grading report and it is available for every diamond with weights ranging between 0.15 to 1.99 carats.

By adapting to the new technology, GIA has also started providing complete eReport with all 4Cs grading results. GIA also offers laser inscriptions with its reports where a specific diamond’s report number is inscribed on the diamond’s girdle, but it is optional. GIA also offers to inscribe customized messages, texts, logos, symbols, and specific dates that not only give your diamond a personal touch but it is also good for easy identification.

4Cs of Diamonds


So, now as you know the brief history of 4Cs and what each ‘C’ in it stands for, let us have a closer look at them to understand how each of these quality parameters affects the value of diamonds.

Diamond Color- Or the Lack of It!

The color of the diamond is one of the four major parameters to determine the quality of a diamond. It is one of the most important 4Cs that helps in selecting the genuine and natural diamond.

The diamond color actually means no color or lack of color. So, the quality of diamonds is decided by the absence of color. A pure and perfect diamond has almost no hue. It is as transparent as a drop of water. These diamonds get the most premium value in the market.

The degree of colorlessness is measured by the GIA D-to-Z diamond color grading system. The test is performed under regulated light conditions. The results are compared with the master stones with known color values to evaluate the colorlessness of the tested stone.

It is important to note here that many times the color difference is so minute that it cannot be detected by an ordinary person. This slight difference in color recognition actually makes a big difference in diamond quality and therefore it also affects the price of the diamond. So, it is very important to re-evaluate the diamond by GIA’s expert before preparing the final diamond color grading report.

What is the D-to-Z Color Grading system?

It is pretty intriguing why the color grading system is D to Z and not the usual A to Z. Well, it also has an interesting history. Previous to the GIA grading system, there were no standard grading systems available in the world. Many different systems like Arabic (0,1,2,3) and Roman (I, II, III) numbers or descriptive terms like “blue-white”, “pale-yellow”, “gem blue” and so on were prevalent to describe the quality of a diamond. Apart from the above systems, there was another more popular system that used A, B, and C to define the quality of the diamonds.

But all these standards often led to misinterpretation and were not able to define the quality of diamond color exactly. So, GIA started a fresh color scale without any connection with previous standards. So, they decided to use the alphabets without the first three letters which were already a part of one of the old systems. And hence the D-to-Z Color Grading Scale.

In this color notation, ‘D’ represents the colorless diamond while the letter ‘Z’ represents light yellow or brown. From D-Z each letter represents a shade of color.

Diamond Clarity- The Lack of Characteristics

Diamond clarity means no inclusions and blemishes. The absence of blemishes and inclusions in a diamond increases its clarity and in turn its value.

But the big question is how these characteristics get attached to a diamond?

Well, as we know, the diamond is a form of carbon. Excessive heat and pressure deep down into the earth converts this carbon into diamond. During this process, the internal and external characteristics of carbon and eventually the diamond undergoes a lot of changes. These characteristics so displayed by the diamond are called the inclusions and the blemishes respectively.

So, while determining the clarity of diamonds these characteristics are checked against their numbers, size, nature, and position. The clarity is also determined by the effect of these characteristics on the appearances of these characteristics.

Like GIA Color Grading Scale, GIA also created a fresh Clarity Grading Standard as there were no proper standards to define diamond clarity. They categorized clarity in the following 6 categories referred to as the GIA Diamond Clarity Scale:

  1. FL (Flawless): No characteristics
  2. IF (Internally Flawless): No inclusions
  3. VVS1 and VVS2 (Very, Very Slightly included): Minor inclusions difficult to detect by an expert
  4. VS1 and VS2 (Very Slightly Included): Minor inclusions detectable with effort
  5. Sl1 and Sl2 (Slightly Included): Noticeable inclusions
  6. I1, I2, and I3 (Included): Obvious inclusions that adversely affects the clarity of the diamond.

Sometimes these characteristics are so minute that only a professional grader can observe otherwise the gemstone appears to be transparent. For instance, VS1 and VS2 apparently look almost the same but quality and cost-wise they are quite different from each other.

Diamond-Cut- The Interaction with Light

Diamonds are known for their ability to transmit light and for their intense shine and glitter. Generally, we connect a Diamond cut with its shape but a diamond cut is the interaction of the diamond with light. Perfect interaction with lights requires a high level of skill and precision in cutting the diamond.

The perfect cut represents the best quality as well as the best value of a diamond. The Diamond cut grading is the most difficult grading among all 4Cs. It is a very complex and tedious process to analyze and determine the cut of a diamond. Some factors determine the quality of the diamond cut. They include;

  • Brightness: Intensity of the white light that reflects from a diamond
  • Fire: Scattering of white light into a spectrum.
  • Sparkling: The successive light and dark patterns created by precise cuts coupled with the sparkle generated by the diamond.

There are many other factors also included in GIA’s cut grade such as design, girdle thickness, symmetry, the ratio of weight and diameter, and quality of the polish.

The GIA’s Diamond Cut Grade has a standard scale that ranges from Excellent to Poor to define the quality of cuts.

Diamond Carat Weight- The Apparent Size

It is simply the weight of the diamond. Previously when carats were not in trend carob seeds were used to measure the weight of the diamond. Today carat is used as a measuring unit for gemstones throughout the world.

One carat is equal to 200 milligrams. For precise measurement, each carat is further subdivided into 100 parts. So, you can measure the carat weight up to the hundredth decimal places and the least that you can measure is 2 mg or 0.01 carat. There is a general terminology used to describe the weight of a Diamond. If it weighs less than one carat it is described by its points, for example, a diamond weighing 0.45 carat is said to be a ‘forty-five pointer.’ However, the higher than 1-carat diamond is described as per the normal number system, like 1.25 carat is described as ‘one point two five carats.’

The price of Diamond increases in proportion to its carat weight due to simple economic reasons for low availability and high demand.

However, carat weight is not the only factor to determine the cost of a diamond. Diamonds with similar carat weight also have different rates depending on the other 3Cs.

Diamond Grading Standard: The 4Cs

GIA has the responsibility to grade the world’s most precious diamonds and produce an authentic grading report.

GIA determines every gemstone to identify synthetic or man-made diamonds that are also known as lab-created diamonds and look-alike diamonds. Expert diamond graders examine each diamond very carefully and minutely to assess the 4Cs of the diamonds.

How to grade Diamond Color?

Background and light sources play a vital role in the assessment of diamond color. The difference in the interpretation by different individuals can also impact the assessment. So, to ensure uniformity, consistency, and correctness of results following steps are followed while assessing the diamond color:

  1. Standard lighting and viewing conditions are perfectly maintained.
  2. Minimum two color-graders examine the gemstone and submit their independent report.
  3. If the results of both the graders are in agreement then the final report is prepared as per their common assessment report.
  4. If the results do not match then the stone is sent to a third color grader without revealing the reports of the other two.
  5. The three reports are then compared to reach a point of consensus.
  6. The testing of the diamond continues until a consensus is reached based on facts and figures.

How to determine Diamond Clarity?

The clarity grading examination also follows almost the same process as described above but with a few differences:

  1. The examination is carried out under a microscope with 10X magnification.
  2. One preliminary grader checks the characteristics of the diamond and also the treatment carried out on the diamond if any.
  3. Two clarity graders then examine and plot the diamond characteristics defining its shape and symmetry.

How to Grade Diamond Cut?

Grading Diamond Cut required the most extensive research of 15 long years to develop a grading system. Finally, GIA succeeded in gathering 70K observations on standard round brilliant diamonds falling into D-Z color grades through computer simulation and modeling. Today the system is so robust that it can assess the cut grading of almost 40 million proportion sets.

It grades the cut from Excellent to Poor that assesses the overall appearance and brightness level of the diamonds. It also assesses the fire and scintillation of a diamond. GIA can also identify if the diamond is natural or lab-created.

How to Measure Diamond Carat Weight?

An extremely accurate and precise electronic micro-balance is used to determine the diamond carat weight that can give an accurate weight result up to the fifth decimal places. GIA uses optical measuring devices to evaluate the facet angles, segments or proportion, and measurements of a diamond.

Why is the Diamond Grading Report Important?

  • A grading report of a diamond ensures the authenticity of the diamond you are going to purchase.
    • A grading report contains all the vital characteristics of a diamond.
  • This GIA diamond grading report assures that you are going to buy a real diamond.
    • You also come to know about any treatment carried out on the stone to enhance its color and clarity.
  • GIA is an independent research and educational institute that is not involved in the selling of diamonds and provides unbiased scientific information about the gem.
  • A GIA Diamond Grading Report provides a detailed evaluation report of color, cut, clarity, and carat weight including a plotting diagram representing the clarity characteristics of the diamond.
    • It also identifies and reports the country of origin of the diamond.
  • GIA takes all precautions to maintain the sanctity of the report and protect it from any malpractice or forgery.
    • With the GIA report, a buyer can be confident of getting the desired quality of the diamond.

4Cs Diamond Buying Guide

Assess 4Cs of Diamond Quality

After learning about the 4Cs of Diamond quality above, you can now understand how to buy a diamond. This information not only helps you to learn about the quality of diamonds but it also gives you an idea about the diamond’s price and value.

It doesn’t matter how beautiful a diamond looks from the outside; it is impossible to judge its quality just from its external appearance. Understanding the 4Cs of diamond quality helps you to assess the quality of the diamond and also know how to purchase an original diamond. These 4Cs are the key quality parameters that make a diamond, a diamond.

Buy from a Reliable Jeweler

Choose a jeweler who is genuine and reliable. You can find out a professional jeweler trained from an internationally recognized program such as GIA Graduate Gemologist or Applied Jewelry Professional diploma programs. Professionally trained jewelers will explain to you the 4Cs diamond quality. Besides, they will educate you about the difference between the fake and the original gemstones. Moreover, they will also offer you a wide variety of diamonds that suit your budget.

Request for the Diamond Grading Report

GIA diamond grading report provides unbiased scientific information such as clarity, cut, color, and carat weight of the diamond. It is proof of all the characteristics a diamond possesses. Through GIA reports you can get exact details of diamonds which you cannot know otherwise through your normal observation. After getting GIA reports you are pretty sure that you have bought a good quality diamond.

Protect your Diamond

This is one of the factors that most of the buyers ignore to consider. Ensure your diamond as soon as you purchase it. Insurers always go with the GIA report to evaluate its value. It is suggested to conduct a thorough investigation and check for the authenticity of the insurer and clarify each point of the insurance policy before you proceed further.

To further protect your diamond against theft you can also laser-inscribed your diamond with its GIA report number. You can provide the number to the relevant agency for verification in case the gem is stolen or lost.

How to Take Care of a Diamond?

Diamonds are the hardest gemstones and are highly durable. They are scratch-resistant, and also maintain their shine and glitter for a long time. But they also require good care to keep them sparkling forever.

  • Insistent sharp blows can cause serious damage to even the strongest gemstones.
  • Besides, due to similar hardness, keeping two or more diamonds together can damage all of the precious stones.
    • It is recommended to store the diamonds and diamond jewelry separately in a soft bag.
  • Apart from protecting them from the harsh blows, you also need to take care to prevent them from getting loose or detached from the ornament.
    • To ensure this, you should avoid putting excessive pressure on the gem piece.
  • To clean your diamond jewelry you can simply wipe it out with a soft cotton cloth.
    • For intense cleaning use warm water with mild soap, and clean the edges using a soft brush.
  • To ensure safety, it is recommended to periodically clean the jewelry and visit the jewelry shop to ensure its setting.
    • Proper maintenance of the diamond makes it durable and helps maintain its sparkle.


In the above article, we have discussed all the parameters related to the 4Cs diamond quality i.e. Color, Cut, Clarity, and Carat weight. All these 4Cs play a vital role in providing the characteristic beauty and durability to the diamond. Every ‘C’ is important for a diamond to be a diamond.

Carat weight is of course the most known factor associated with the value of the diamond. But we should not forget about the other 3Cs of the diamond quality. A high-quality Cut increases the beauty and brilliance of the diamond. Good Color and Clarity grade also help to increase the value of diamonds.

So, whenever you are going to purchase the diamond always remember to strike a balance between quality and value by using these 4Cs. It will help you get a good quality diamond within your planned budget.

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