Diamond 4C’s

the 4C's of Diamonds

Bottom Line Recommendations

  • A diamond is evaluated based on the 4Cs that were developed by the GIA. A diamond is given a higher grading when it appears colorless. Diamonds in the D, E and F color grade have the highest value. Take a look at a D color round cut here and compare it with G color here.
  • Clarity is the lack of blemishes and inclusions in a diamond. The less visible they are under 10X magnification, the higher the clarity grade of the diamond and the higher its value. Take a look at this VS2 oval diamond here and compare it with a VVS2 oval diamond here. Note that you can still go lower on the clarity scale and get a great deal. However, ensure that the diamond is eye-clean. View an eye
  • The cut is considered the most important factor when evaluating the diamond. It determines the brilliance, fire, and scintillation of the diamond. When evaluating the diamond cut, do not go below a Good cut as any stone below this will not reflect light optimally.
  • The carat weight refers to the size of the diamond. The larger the diamond, the easier it gets to notice any flaws and blemishes as you can see here. Always make sure that you have access to 360-degree videos of the diamond. At the end of the day, it’s all about how the diamond appears. We recommend James Allen and the Blue Nile. They offer excellent service and high-quality images and videos of the stone.

James Allen Diamonds

If there is one thing that makes diamonds special, it’s their uniqueness. Every diamond has individual qualities that set it apart from the rest.

Before the mid-20th century, many people simply went to a dealer and picked the most stunning stone that they could find. At the time, there was no standardization on judging the quality of a diamond.

However, thanks to the GIA, which came up with the first diamond standardization process, these timeless stones can now be judged based on the 4Cs. These are the Color, Clarity, Cut and Carat Weight and is a method that is used universally for judging the quality of a stone.

One of the main advantages of the 4Cs is that people can describe the same thing about a stone regardless of their location around the globe. Second, the buyer knows what he or she is getting.

Let’s take a look at each of the 4Cs is greater detail.


Color evaluation of a diamond is based primarily on its absence. What is considered a chemically pure diamond is one that has no hue. It is therefore given a higher quality value when it looks colorless.

The GIA has a grading system from D-Z. This is used to compare the diamond after it’s placed in controlled lighting and compared to master stones in each grade.

Some color distinctions between grades are tiny and most will not be seen by the naked eye. However, their effect on the quality and consequently the price of the diamond is huge.

The GIA color grade begins at D. Before its development, other grading systems were used. These were not standardized. There was the A, B, C system. The downside of this method was that there wasn’t any clear definition.

There was also the roman numbers I, II, and III as well as the Arabic method 0, 1, 2, 3 methods. Because of all these different methods, there was a need to come up with a system that was different from the rest and one that could provide a better grading system.

One thing to keep in mind is that diamonds that are in the Z color grade are not fancy color diamonds. Fancy color diamonds can be referred to as brown or yellow-colored diamonds and those that have more color than the Z master diamond.

The less the color the higher the value

That is when everything else is left constant. Diamond color is quite an important factor to consider when buying your stone. That said, the less color the diamond has, the higher the price.

ColorlessNear colorlessFaintVery LightLight


As you can see above there are 5 groups in the GIA color grade.

Colorless diamonds are in the D-F range. They are the rare rest and therefore the most expensive.

The G-J diamonds aren’t noticeable by the untrained eye. However, a trained grader will notice.

K-M diamonds have a hue but it is not easy for the untrained eye to see.

N-R is Very Light diamonds. The untrained eye can notice subtle color in the stone.

S-Z are categorized as Light. Color can easily be seen in stones. While the diamond appears to have a slightly yellow or brown color, it doesn’t have sufficient tint to be considered a fancy colored diamond.

A grading lab determines the diamond color grade

The untrained eye will not be able to determine color distinctions, especially on diamonds higher up on the color grade. However, they have a significant impact on the price of the diamond. A gemological laboratory will determine the diamond occur grade. They have the equipment and the expertise to provide an unbiased grading.

There is a strict procedure that is used to assign a diamond to its color grade. The lighting should be standard and the background as well. There is also the right method of holding the diamond when viewing and the stones are also compared to master stones.

The master stones are color stones that have a specific grading.

A different method for grading colored diamonds

When it comes to fancy colored diamonds, the color is the most important consideration. They can come in a variety of different colors which include yellow, brown, red, pink, blue, green, black, purple or orange.

Note, however, that colored diamonds are not those on the normal GIA color scale that could be slightly gray, slightly yellow or slightly brown.

Unlike the normal color grade which judges the stone based on the lack of color, judging fancy colored diamonds is based on the presence of color.

Some terms are used to describe the color of the fancy diamonds. These included Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep and Fancy Vivid.


The diamond clarity grade determines the lack of blemishes and inclusions on the stone. The beauty of the diamond is determined in part by the clarity of the stone.

Blemishes are not flaws, however, and the stone with the least blemish will cost significantly more than one with inclusions or blemishes. These are mostly located on the surface of the stone.

There are a number of factors that can cause inclusions. The formation of the diamond, the cutting process as well as general wear all have a part to play.

The inclusions may be totally enclosed in the diamond. Some may be on the surface while others may extend from the surface to the interior of the stone.

Less blemishes more value

The lesser the blemishes the higher the value of the stone. Finding a diamond that has no blemishes is very rare and this pushes up their price. Diamonds placed under 10X magnification and show no blemishes will be considered flawless.

However, such stones are extremely rare. There are many jewelers who will never come across such a diamond in their careers.

Some inclusions are visible to the naked eye. These diamonds are less expensive. Many stones will fall into two main categories. Either the inclusions can be seen with the naked eye or some will only be viewed with magnification.

Some diamond cuts will show inclusions more visibly than others. It is much easier to view inclusions in the emerald cut but harder in the round cut.

Note however than when it comes to the beauty of the stone, inclusions will affect the diamonds more than blemishes. This is mainly due to the fact that blemishes can be removed. A stone can be recut to take off the part that has blemishes.

The diamond clarity scale

The GIA was responsible for coming up with the diamond clarity scale back in the 1950s. One of the factors used to determine the clarity of the diamond on the scale is the visibility of the blemishes and inclusions when looked under 10X magnification.

FlawlessInternally FlawlessVery Very Slightly Included 1Very Very Slightly Included


Very Slightly Included 1Very Slightly Included 2Slightly Included 1Slightly included 2Included 1Included 2Included 3


Flawless—there are no inclusions or blemishes that can be seen under 10X magnification.

Internally Flawless—there are very tiny blemishes and no inclusions at all under 10x magnification.

Very Very Slightly Included 1 and 2—very minute inclusions can be seen.

Very Slightly Included—very minor inclusions can be seen.

Slightly included 1 and 2—inclusions are noticeable and easy to see under 10X magnification.

Included 1, 2 and 3—inclusions can be seen with the naked eye.

Another term that you will also likely come across when considering the diamond clarity is eye clean. It simply means that the inclusions art not visible with the naked eye.


The diamond cut is considered the most important factor when evaluating a diamond. A well-cut diamond will affect just how well the facets reflect light and how brilliant it is. The cut grade of a diamond combines the symmetry, proportions as well as the polish.

A poorly cut stone will not reflect light efficiently resulting in less sparkle and brilliance. The sparkle is a result of the light bouncing off the sides and facets of the stones and then being reflected back to the observer.

Like clarity or color, the differences in diamond cut grades are very visible to the naked eye. A stone that is low on the cut grade will be visibly different from one that is high on the cut grade.

It is always a good idea to up the cut grade first before you can move up the carat weight when choosing your stone.


This cut grade represents diamonds that provide the most brilliance and the most fire. All of the light that enters through the diamond will be reflected towards the observer.

Very Good

Diamonds with a Very Good cut will reflect back most of the light that enters the diamond. While it is not as expensive as the excellent cut diamond, it still provides impressive brilliance and fire.


If you are on a budget then a Good cut is a good choice stone. Most of the light that enters the diamond will be directed back to the observer providing impressive fire and brilliance. However, it is not as bright as the previous two.


This diamond cut will not have an optimal light reflection. Some light will leave the stone from below or through the sides of the diamond. Because of this, the diamond will not have much fire or brilliance.


This diamond cut looks dull. It is advisable to avoid diamonds of this cut scale as they will not have any brilliance. Some are so terrible that jewelers will not sell them.

Terms when evaluating diamond cut

When judging the cut of a diamond you will come across a few popular terms. These are brilliance, fire, and scintillation.

These are the three main things through which a diamond cut is based on.


When you look at a diamond, you may notice some light refractions that seem to produce the rainbow colors. This fire of a diamond. A high-quality diamond has the ability to show its fire even in low light situations.


The facets of the diamond results in brightness. This is also a result of the ratio and the proportions of the facets. The best-cut diamond will not have any light leakage on the downside or the sides of the stone and is said to have brilliance.


When you take a well-cut diamond and you place it in the light, you will notice flashes of light and dark spots. This is the scintillation of the diamond. It results in sparkle and the more the sparkle the higher the scintillation.

Understating proportion, symmetry and polish 

The proportion, polish, and symmetry of a diamond will determine its cut quality.


This is the relationship between the size, angle, and shape of the facets of the diamond. It is this proportion that will influence the diamonds reaction to light. The right proportions and angle of the facets will maximize the amount of light that will be reflected back to the observer.


It is considered one of the most critical factors that influence the diamond cut quality. If the diamond has symmetry, the two halves of the diamond will be properly aligned and well balanced. On the other hand, if the facets are not symmetrical, there will be less sparkle, fire, and brilliance. A gemologist will place the diamond under a 10X magnification and observe the size, shape, and angle of the facets.

How the crown and the pavilion are aligned and how the culet is placed is also checked.


Polish is how well finished the diamond is. After the cutting process, the stone is polished resulting in a smooth finish. Every single facet needs to be polished to ensure that it has the most brilliance.

Carat Weight

The last on the list of the 4Cs of diamond quality is the carat weight. Carats are the international units by which gem weights are measured. A carat is equivalent to 0.20gramms.

However, you should never confuse carat with karat. The latter is used to measure the fineness of gold. Its abbreviation is K.

How diamonds are measured

Often a diamond will be placed on an electronic microbalance scale. When buying diamonds, the carat weight will be given two decimal places. However, when being weighted by the diamond lab, it will be measured to up to 5 decimals for high precision.

Keep in mind that the price of a diamond is determined by taking the carat weight and multiplying by the price per carat. The larger the diamond the higher its costs.

Diamond size is different from carat weight

It’s easy to compare the diamond size to carat weight. However, this is not always how it works. Different gems have different levels of density. This means that you can have two gems that are similar in size but they have different carat weights.

Think of it this way, a ruby is denser than a diamond of the same size.

The cut of a diamond will also determine how an observer may perceive the size. One diamond might have a thick girdle and another might be too deep. Some weight can be hidden under the girdle. Because of this 1.20ct diamond may look the same as a 1.0ct diamond.

This is why it is not the best idea to use the weight of the diamond to estimate its size.

Size isn’t everything

For those looking to spend a good price on a diamond, finding the best combination of color, cut, clarity and carat weight is essential. Many people, however, will tend to focus on the carat weight. Other people would prefer a diamond that has plenty of brilliance and sparkle, and one that catches attention in an instant.

However, it’s important to note that going for the largest diamond isn’t always the best thing. A diamond could be large but the wrong cut will lack the best light action. This means that you should focus on a stone that has the right cut first.

Some diamond cuts are difficult to evaluate by carat weight alone such as the emerald cut. The long and rectangular shape makes facets highly visible. Buying a large emerald cut diamond will look less appealing due to going for a smaller diamond.

Something to always keep in mind also is that there is a difference between the total carat weight and the total weight of a diamond.

Consider a halo diamond setting where a center stone is surrounded by multiple smaller diamonds. In this case, the total carat weight is the total of all the stones on the ring while the carat weight refers to the weight of a single main diamond on a ring.



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