Diamond the 4 c’s: Beginners guide to diamond grading

Diamond the 4c's

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Let’s break down real quick this thing called “Diamond: the 4c’s“;

Not all diamonds were created equal; some carry imperfections (like birthmarks). For that reason, we need a way to grade and evaluate each diamond, hence the 4c’s:

  1. Carat: The weight of the diamond in carats (1 carat = 0.2 grams)
  2. Color: Diamonds’ color can range from yellow to colorless. A colorless diamond is more desirable
  3. Clarity: Measures if the diamond carries and flaws, their size, and location. The clearer, the better.
  4. Cut: The proportions, measurements, angles, and finishing details control the level of sparkles we see. A higher cut equals more brilliance and sparkles.
 

After grading the diamond by this international diamond grading system, also known as diamond the 4 c’s, the seller can evaluate its worth and come up with a price. Since no diamond is equal, you can find diamonds that share the same grades yet are sold for a different price. By inspecting the diamonds correctly, we can pick the best one.

Let’s run a quick test. Here is a picture of a round brilliant diamond; the diamond’s quality is a secret. Can you tell the diamond’s color grade? clarity and carat? Test yourself. Click to find out.

Test yourself: What are the grades of this diamond?

Table of Contents

One might wonder what’s the difference between a diamond that costs $2,000 and another that is sold for $10,000 if both look almost identical to the naked eye. That’s a fair question, but if appropriately inspected, you can understand the difference between each stone. 

Not all rough diamonds were created equal in nature. Some carry more flaws, while others are clearer. There are different sizes and colors as well. 

Considering many factors, the GIA (The gemological institute of America) created a simple system called The “4C’s of diamonds.”

Grading is a vital process that makes it easier to identify diamonds without physical verification, leading to quality assurance. It also means buyers can rest assured about diamond qualities without a personal inspection. Furthermore, grading also helps reduce adulteration and fraud. Last but not least, it serves as a price determinant. 

Without further ado, this article walks you through the process of diamond grading by covering the following areas in detail:

1. Understanding the 4Cs: the ultimate diamond guide.

2. Which Is the Most Important of the Four Cs? 

3. How to buy an engagement ring using the 4C’s.

Understanding the 4Cs: The Ultimate Diamond Guide

As said earlier, the 4Cs in the diamond context represent:

1. Carat

Carat is a unit of measurement used to express the weight of diamonds and other gemstones such as gold, ruby, emerald, and pearl. And it has been used in the diamond trade since ancient times(sometime after 1330, according to CBS News).

A metric carat is equal to 200 milligrams(0.2 grams). Please note that there’s a difference between “carat(CT/ct)” and “karat(k/kt)”, the latter which measures gold purity and has nothing to do with weight. 

One might wonder why carats but not any other unit of measurement e.g, milligram, gram, or kilogram. To answer this question, I’ll tell you an exciting story about the origin of carats. 

You see, the word “Carat” comes from Greek, meaning “Carob Seed.” Coming from the locust tree, a fast-growing flowering plant belonging to the Fabaceae plant family, the carob seed was a vital food flavoring ingredient. It was also an essential source of livestock food. 

During this time, there were no modern weight measurements, yet there was a need to measure gemstones accurately and reliably. Since the carob seed offered a consistent weight as well as size, gemstone traders compared the weight of diamonds to the seeds. It proved to be a very accurate metric measurement technique for many centuries.

N/B: To date, gemologists and jewelers have held on to diamond carat weight as the standard unit of measurement for diamonds and other gemstones.

All things being equal, the price increases with the diamond carat weight. That’s because diamonds with greater carats tend to be larger, rarer, and hence more desirable. However, two diamonds of the same carat weight can be priced or graded differently due to color, clarity, and cut. 

2.5 carat to 0.5 gram

2. Color

When it comes to grading according to color, diamonds are often graded by how colorless they are. This is done by comparing the diamond to a sample diamond of known color under controlled lighting together with precise viewing conditions. Through that, experts can spot the subtle color distinctions between diamonds, which are otherwise invisible to the naked eye. These subtle color differences make a huge difference in the gemstone’s quality as well as price. 

Now, the GIA’s color-grading scale is the industry standard for diamond grading according to colorlessness. It features a color scale that runs from colorless to light with corresponding letters as follows:

  1. COLORLESS: D, E, F.
  2. NEAR COLORLESS: G, H, I, J.
  3. FAINT: K, L, M. 
  4. VERY LIGHT: N, O, P, Q, R.
  5. LIGHT: S, T, U, V, W, X, Y, Z.

As a helpful rule of thumb: the less color, the higher the value of the diamond. The exception to this rule is colors that lie outside the colorless range e.g fancy colors: red, blues, and pinks. 

Did you know that there are diamonds with extraordinary colors such as red, blue, and pink?

i. Red diamonds are the most expensive, costing at least $1,000,000 per carat. These diamonds are primarily found in Australia, Africa, and Brazil. Moreover, they are so rare that only about 20-30 authentic pieces that are hardly half a carat are known to exist.

diamond the 4c's red color
The Argyle Everglow, a 2.11-carat Fancy Red diamond, is the largest red diamond in the 33-year history of the Argyle Pink Diamonds Tender

ii. Enigmatic and captivating, blue diamonds are the second-rarest and most expensive type of diamonds. Priced beyond $100k-$200k per one carat, these diamonds are mined in only three places worldwide. These places are South Africa(the Cullinan mine), India(Golconda Sultanate mine), and Western Australia(the Argyle mine). 

iii. Costing between $30k-100k per carat, pink diamonds are the third most expensive type of diamonds on the market. Most of these diamonds come from Australia (the Argyle Mine).

Red, pink, and blue diamonds are a different story though. Their fancy colors are attributed to a distortion in the crystal lattices. This occurs due to tremendous pressure from all directions and intense heat after the stones’ formation.

This displaces many carbon atoms from their regular positions, altering the qualities of the light reflected by the gemstones. This unique configuration of the molecules gives the stones the special colors mentioned above. 

Diamonds with fancy colors are unique because of their structure and also the fact that they are unbelievably rare.

3. Clarity

Another factor that determines the grade and quality of diamonds is clarity. And knowing what it truly means will help you better understand diamond grading and qualities. 

For starters, diamond clarity refers to the absence of inclusions as well as blemishes in a piece of diamond. Simply put, inclusions and blemishes are structural imperfections that affect the grading of diamonds based on clarity. 

diamond the 4c's clarity
An I1 clarity diamond with lots of inclusions

Inclusions come about as a result of the extreme heat and pressure that carbon undergoes during the diamond formation process. Blemishes, on the other hand, occur during cutting, following the formation process. These imperfections include extra polish lines, burns, or facets created due to the excessive heat under which the gemstone is subjected during cutting. 

When grading diamonds according to clarity, experts will evaluate a couple of things regarding the above imperfections. For example, they’ll pay attention to the inclusions and blemishes’ number, size, nature, and position. In addition to that, they’ll consider how these faults affect the gemstone’s overall appearance. They’ll do so keeping in mind that no diamond is 100% clear and that the closer the gemstone comes to purity, the better its clarity.

Notably, many experts will use the GIA Diamond Clarity Scale when grading diamonds according to clarity. This scale comprises six categories represented by letters alongside a combination of letters and numbers. Some of the categories are divided into up to 11 specific grades;

1st Category: Flawless (FL)

The expert will place the diamond into the Flawless(FL) category if the gemstone’s inclusions and blemishes are invisible even under 10x magnification with a microscope.

2nd Category: Internally Flawless (IF)

The expert will categorize the gemstone as “Internally Flawless(IF)” if blemishes are visible on the outside, but inclusions are invisible on the inside under 10x magnification.

3rd Category: Very, Very Slightly Included (VVS1 and VVS2)

Diamonds with inclusions extremely difficult to detect with a microscope set to 10x magnification can be categorized as Very, Very Slightly Included (VVS1 and VVS2). Usually, the imperfections are too minute to see, even for a skilled grader using a microscope. 

4th Category: Very Slightly Included (VS1 and VS2)

Diamonds graded as VS1 and VS2, according to clarity, contain minor inclusions. These imperfections require effort to see under 10x magnification.

5th Category: Slightly Included (SI1 and SI2)

SI1 and SI2 are characterized by reasonably noticeable inclusions under 10x magnification. These are considered lower-quality diamonds. 

6th Category: Included (I1, I2, and I3)

I1, I2, and I3 are often treated as the lowest quality diamonds because they have inclusions that are very easy to see under 10x magnification. These easily noticeable structural imperfections reduce their transparency as well as brilliance.

Not eye-clean Eye-clean

Interestingly, depending on the size of the diamond, inclusions and blemishes in diamonds tend to be difficult for the naked eye to spot. 

To the bare and untrained eye, I1-3 clarity diamonds may look the same as FL or any other clarity grading diamond, even though these diamonds differ significantly in their clarity grade and overall quality. This mistaken judgment is why clarity assessment is vital to grading diamonds. 

Wondering how the GIA Clarity Scale came to be? Well, it developed to curb the problem of jewelers using relative and imprecise terms e.g “pique” or “loupe clean,” to describe their products. These terms were misleading buyers who often ended up paying more unknowingly for lower diamond quality. 

Today, if you inquire about a diamond’s clarity, the jeweler would most likely use terms like FL, IF, VVS1, and so on, to describe it. This is regardless of the language in which both of you are communicating, whether English, French, or any other. It’s an international diamond grading system.

4. Cut

Finally, diamonds are graded according to how they are cut (how well-proportioned the gemstone dimensions are and how these surfaces are positioned to transmit light and deliver brilliance and sparkle. The diamond’s facets interact with light and control the light performance. The higher, the better.

This means that the diamond cut’s quality is crucial to the diamond’s beauty and value. The best diamond cut grades are characterized by precise artistry and workmanship, all of which ensure perfect proportions, symmetry, and polish. All these qualities combined deliver the most brilliance and sparkle.

diamond the 4c's cut

There are more than ten diamond shapes that are considered common. These include but are not limited to round cuts, cushion cuts, princess cuts, emerald cuts, oval cuts, and marquise cuts. The rest are pear cuts, Asscher cuts, radiant cuts, and heart-shaped cuts. 

Diamond’s cut is graded as:

  • excellent/ideal
  • very good
  • good
  • fair
  • poor
 

Round brilliant diamonds are considered excellent cuts because they yield the highest level of brilliance, whereas princess cuts are seen as very good cuts since they provide exceptional brilliance. Likewise, cushion cuts are considered good as they offer sparkle and brilliance. Meanwhile, emerald cuts are equally fairly popular since they showcase a little brilliance, whereas Asscher, marquise, and radiant cuts are seen as poor cuts. That’s because they provide almost no brilliance or sparkle.

Who Invented The Diamond 4c's?

The GIA (Gemological Institute of America) is a nonprofit organization that was established in 1931. It is the world’s foremost diamonds, gemstones, and jewelry authority. The GIA developed the 4c’s diamond grading system, which is now used by jewelers all over the world to grade diamonds accurately.

The GIA is also responsible for setting the standards for diamond grading and providing education and training to gemologists and jewelry professionals. Additionally, the GIA operates the world’s largest laboratory for diamonds and gemstones, which is where diamonds are graded according to the 4c’s system.

IGI vs GIA lab diamond certificate

How To Buy An Engagement Ring Using The 4 C's

Each buyer looks for something different, you need to ask yourself two questions: what is most important for you:

  1. What diamond carat weight size are you aiming for?
  2. What matters most to you? size or brilliance?
 

Since there is no reason to get a diamond with no sparkles, we won’t compromise over cut, so stick to triple x diamonds, meaning they have:

  • excellent cut
  • excellent polish
  • excellent symmetry
 

Now let’s see how we reach your goal.

If you are interested in the largest carat within your budget:

  1. Compromise over clarity: for 0.1-2.00 carat weight diamonds, focus on SI2-VS2 clarity diamonds. If you want to go even bigger, larger than 2.00 carat, focus on VS2 clarity and higher. Keep in mind, the larger the diamond, the easier it is to spot the flaw with the naked eye.
  2. Compromise over color: If you plan on getting white gold or platinum settings, focus on J-I color grades. Find a relatively bright diamond to the band, and look colorless to the naked eye. If you want a yellow gold or a rose gold setting, feel free to compromise even more on color, and go with M-K. The setting will reflect its color into the diamond, so there will be a yellowish tint anyway.
diamond the 4c's buying guide the largest diamond
Example: Largest diamond within a $6,000 budget

If you are interested in getting the best balance:

  1. Clarity: As long as the diamond is eye-clean, meaning you cannot see the flaws with the naked eye, you can go with SI1-VS2 clarity grades. This way you’ll be able to invest more in a larger diamond.
  2. Color: The sweet spot of the color scale is I-H colors. When picked right, the diamond will appear completely colorless to the naked eye, you won’t see any yellowish tint. Remember, as long as you don’t have another diamond to compare to, a good I-H diamond will appear colorless.
  3. Look for the largest diamond within your budget while considering the first two rules above (SI1-VS2 clarity, I-H color).
diamond the 4c's buying guide the best balance
Example: Best balance within a $6,000 budget

If you are interested in the most brilliance, fire (blue and yellow reflections) and sparkles

The diamond’s cut is your friend. Look for Hearts and Arrows diamonds. Only the top 1% of round brilliant diamonds reach this cut level due to perfect symmetry. It shows much more brilliance, fire (blue and yellow reflections), and sparkles than any other ideal cut diamond. Those diamonds are the diamond industry’s flagship and are considered a masterpiece.

However, as expected, they come at a higher cost. Depending on your budget, you might need to compromise over diamond weighs (carat), color, and clarity. But same as before, always pick an eye-clean diamond, at least SI1. Depending on the metal of your diamond engagement ring, pick the right color as mentioned before.

diamond the 4c's buying guide premium cut
Example: The most brilliance within a $6,000 budget

Which Is the Most Important of the Four Cs?

There are two ways to look at it. The right way to look at it is to understand what gives a diamond the WOW factor. The size? or the sparkles?

Jewelers perspective

Many jewelers don’t care about most factors. They believe that the WOW factor comes with the largest diamond. For that reason, they would prefer to compromise over cut and lose the brilliance and sparkles of the diamond. Not only that, they would compromise over color and clarity as well.

I don’t agree with that, however for diamond jewelry, for example, tennis bracelets, you can compromise a lot over clarity.

Diamond experts perspective

Diamond experts believe the opposite. What’s the point in paying thousands of dollars if the diamond doesn’t shine and sparkle?

For that reason, diamond experts would prefer to stick with triple X diamonds, making the cut factor the most important of them all. Only after making sure the diamond shows a good brilliance, would they move on to carat weight, eye-clean clarity, and decent color.

The bottom line, if you ask a jeweler, they would say carat weight is the most important of the four Cs. If you ask a diamond expert, they would say the cut is the most important factor.

So, what’s the right answer?

It depends on your priorities.

Conclusion

Diamonds are not all created equal, so we need a way to grade and evaluate each diamond- this is done through the 4 c’s: carat, color, clarity, and cut. You may prioritize different factors depending on what you’re looking for in a diamond. For example, if you want the largest diamond possible, carat weight would be the most important factor; however, if you are looking for maximum brilliance and sparkles, cut would be the most important factor. No matter your priorities, make sure to choose eye-clean diamonds with at least SI1 in clarity.

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