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4Cs of Diamonds

Diamond is one of the world's most valued natural resources, not to mention one of the most highly desired gemstones. Diamond is naturally made with an enormous variety of characteristics, making each individual diamond unique. The combinations of these characteristics determine the quality and value of a diamond.

The Four C's stand for Cut, Color, Clarity, and Carat Weight . The diamond grading system has transformed the diamond trade and today is used by nearly every professional in the industry and diamond enthusiasts across the globe. Because individual diamond varies so immensely in quality and price, it is vital for consumers to be familiar with the Four C's as well. We've outlined the basics of this grading system below, to help give consumers the resources they need to make educated purchases.

The 4Cs of a diamond are the most important factors that play a critical role in determining the price of a diamond. These include diamond carat weight, diamond color, diamond clarity, and diamond cut. While the first three a natural elements, the fourth one depends on the quality of the craftsmanship, so cut is a human factor.

It is very important to note that you would have to learn more about each C in order to understand how important that C is while considering a diamond. Please also note that there could be a big difference between a diamond that has the same grading in terms of the C4s, so understanding the details of each C is important.

Parts of a Diamond

Cut of Diamonds

The diamond cut is the most important element to consider when buying a diamond. The cut is the biggest factor in creating sparkle and fire, and without a high cut grade even a diamond of high quality can appear dull and lifeless. A diamond cut poorly and too deep can face-up smaller than it actually is. A well-cut diamond will direct more light through the crown. A diamond with a depth that's too shallow or too deep will allow light to escape through the sides or the bottom of the stone.

A diamond’s clarity, colour and carat weight cannot be altered, but it is a high quality cut of diamond that can release that extra special sparkle.

Ideal Cut

A well cut diamond will reflect ligth back through the crown of the diamond and into the observer's view.

Shallow Cut

if a diamond is cut too shallow ligth will escape through the lower part of the diamond, the pavilion, reducing the diamond's sparkle to the observer.

Deep Cut

A deep cut diamond will have a similar effect to the shallow cut, refracting ligth through the pavilion again.

Grading the Cut of a Diamonds

A diamond’s cut grade is the only factor that is influenced by a human hand. A master cutter will apprentice for at least 10 years before touching a 1 carat diamond. These highly-skilled craftsmen bring the ultimate beauty of the diamond to life by adhering to specific parameters in order to maximize sparkle. Several individual factors are evaluated to determine the cut grade of a diamond including its proportions, depth, symmetry, polish and finish.

The GIA uses the following scale to grade round brilliant diamonds:

    An excellent cut diamond has a maximum amount of scintillation, brilliance and fire. Light enters the diamond and refracts back out with very little light lost. This exceptional grade represents roughly the top three-percent of diamonds.


    A diamond with a very good cut grade will reflect most of the light and will appear somewhat similar to an ideal cut diamond. This diamond will have superior sparkle, brilliance and fire.

  • GOOD

    Reflecting most of the light entering the diamond, this diamond cut has above average beauty. Diamonds with this grade won’t have as much brilliance and fire as higher cuts.

  • FAIR

    Diamonds graded Fair don’t have the optimum brilliance and fire, as they allow a significant amount of the entering light to exit on the bottom or side of the diamond instead of through the top. These are still quality, but not nearly as well performing as a finer cut.

  • POOR

    Diamonds with a poor cut may appear dull because the majority of the light is lost through the bottom or sides of the diamond. With a noticeable decrease in sparkle, even an untrained eye can see a sharp difference between this and higher cuts.

Clarity of Diamonds

This refers to the inclusions (internal) or blemishes (external) held by the stone. A diamond’s clarity is determined under a 10x loupe magnification with the highest grading called Flawless which has no internal or external flaws. Flawless and Internally Flawless diamonds are incredibly rare. We then enter the realms of VVS, VS, SI and I which all include variations of the word imperfect such as very very slightly imperfect, very slightly imperfect, slightly imperfect and imperfect.

It is important to remember that officially these clarity terms only become apparent under 10x loupe magnification and shouldn’t affect your experience looking at your diamond with the naked eye.

The GIA uses the following scale to grade round brilliant diamonds:

Clarity of Diamonds
Flawless Internally Flawless VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3
Very Very Slightly Included Very Slightly Included Slightly Included Included

The Diamond Clarity Scale is segmented into six categories:

Flawless (FL)

A diamond that is graded as Flawless contains no inclusions or blemishes apparent to the grader under magnification.

Internally Flawless (IF)

These diamonds do not contain any inclusions but may contain a very small blemish under magnification.

Very, Very Slightly Included (VVS1, VVS2)

These diamonds may contain inclusions so minute that they are barely visible, even to the trained grader under magnification.

Very Slightly Included (VS1, VS2)

These diamonds contain minor inclusions not visible to the naked eye, but are apparent under magnification

Slightly Included (SI1, SI2)

These diamonds contain inclusions that are visible under magnification, and can occasionally be visible to the naked eye under close inspection.

Included (I1, I2, I3)

These diamonds contain noticeable inclusions that are almost always visible to the naked eye.

Color of Diamonds

Diamonds are graded in colour from D to Z, the scale begins with D (colourless) and finishes at Z (light yellow or brown), a diamond of a light yellow or a brown colour. A colourless stone will allow the maximum amount of light to travel through increasing its brilliance and fire so therefore the whiter a diamond the higher its price.

The Gemological Institute of America (GIA) grades diamond color on a scale of D to Z. D to Z diamonds are also known as white diamonds, even though most diamonds, including H color diamonds and G color diamonds, have varying amounts of color.

It's very difficult to tell the difference from one color grade to another color grade. That's why it's important to compare diamonds side by side. Colorless is the most rare and therefore the most expensive. Yellow is the least rare and therefore the least expensive.

Color of Diamonds
Scale Colourless Near Colourless Faint Yellow Very Ligth Yellow Ligth Yellow

Fancy Colored Diamonds

Fancy colored diamonds are not graded on the same scale as colorless diamonds and are rarer, making them more valuable and expensive.

Carat Weight

Diamond carat is often misunderstood and refers to a diamond's weight, not necessarily its size. When comparing diamond carat sizes, take a diamond's cut into consideration as well: a high-carat diamond with a poor cut grade may look smaller, often cut deeper, than a diamond with smaller carat weight and a better cut.

Diamonds' Size by Carat Weight
Carat Weight 0.50 0.75 1.00
Approx. size
Diameter (mm) 5.0 6.0 6.5

Fifth C of Diamonds

Technically speaking, there are no more C's of Diamonds other than Cut, Color, Clarity and Carat. However, there is another Criteria which we at Diabon, refer to as the Fifth C of Diamond Grading and it is the Certification of Diamonds and we would even go further and state the IGI certificate.

Everybody can issue a certificate specifying the Four C's of a bespoken diamond. But the question is are they qualified and professional enough to do so? (and that assuming they have the integrity to do so). Over the years many reputable jewelry companies issued their own certificate of authenticity as for the diamond's quality and attributes. But those companies have the incentive to lie (or at least to round it up) towards their own sake. A minor "mistake" of grading a diamond as D instead of E means A LOT of money. Therefore, only trust the objective certificate of a gemological institute and the IGI's certificate is known to be strict non-compromising and accurate. Why settle for anything else?