The 4Cs Of Diamonds Explained

Bride wearing solitaire diamond ring

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Picking a diamond for your engagement ring can feel challenging if you’re not too familiar with the many different aspects and specifics of jewelry-grade diamonds. There are lots of things to consider and many shoppers feel tempted to just leave it all in the hands of the sales reps in their local jewelry shops.

This isn’t always a great idea, however, and even then you ought to at least be aware of the basics if you want to get a truly great and fairly priced diamond.

So, to that end, let’s start by explaining the famous 4Cs of jewelry diamonds – Cut, Carat weight, Clarity, and Color. We’ll also tack in a couple more “Cs”, namely Certification and Cleanliness.

First C: Diamond Cut


Gia Diamond Cut Grade Table

A diamond’s cut is arguably its most important characteristic. The GIA grades diamond cut on an Excellent to Poor scale, but most retailers will have their own signature grade for super-ideal diamonds.


A True HeartsTM  diamond by James Allen.

Click on the image to interact with the diamond.

Many people confuse “cut” with “shape” but that’s not actually accurate. The diamond’s cut determines its shape and is typically – but not always – named after it (i.e. Round cut, Cushion cut, Oval cut, etc.) but it goes beyond that too.

The cut also determines the following factors:

  • how many facets the surface of the stone has
  • how well those facets were crafted
  • what the exact dimensions of the diamond are
  • how the diamond was cut from the original piece of diamond rough
  • how much rough was thrown away
  • how well the diamond cutter managed to cut around certain inclusions in the diamond rough
  • how well he or she managed to remove or mask other inclusions present in the finished stone
  • how well the stone has been polished
  • how well its brilliance, fire, and sparkle have been maximized

In short, the diamond’s cut is the one C that makes all other Cs work. You can get a completely colorless and crystal-clear diamond with no inclusions in it but if its cut is dull it still won’t sparkle.

All diamond shapes

Diamond shapes and their cuts

As far as shape is concerned, that’s not insignificant either. Different diamond shapes are utilized to serve different purposes – some maximize brilliance, others retain color, some have a more classic look, while others feel more modern. The most popular diamond shape by far is the Round cut, especially for engagement rings – that’s both because of its classic look and fame, and because of the Round cuts amazing brilliance and versatility.

Other shapes and cuts also look great on engagement rings, however, and shouldn’t be ignored. Many of the more obscure diamond shapes make for even more unique and eye-catching engagement rings, precisely because they are rarer. 

See a range of stunning diamonds here.

Second C: Diamond Carat Weight

Carat weight is the simplest of the 4Cs to explain – it refers to how heavy the diamond is, which is quite important both for its look and for its price.

1 carat is equal to 200 milligrams or 0.2 grams. So, a 1-carat diamond is essentially a 0.2-gram diamond. This may not sound as much but diamonds are relatively light so a ~1-carat is a pretty standard weight for an engagement ring. Some retailers allow you to have a carat size preview of a diamond:

5 carat asscher engagement ring on girl's finger

See this tool here

The importance of a diamond’s carat weight to its overall price shouldn’t be ignored. Larger diamonds are exceptionally rare both because they are scarcely found and because it’s difficult to cut a large diamond out of a piece of diamond rough.

As a result of that, the price of diamonds doesn’t just rise quickly with the increase in carat weight but it also “spikes” very rapidly at certain intervals – usually at each full carat. Probably the most important “price jump” is at the 2-carat weight. This means that the difference between a 1.95 and a 2 carat stone is much greater than between a 1.90 and a 1.95 carat stone.

Another thing to consider here, however, is that bigger isn’t always better. There are several reasons for this:

  1. The inclusions (physical and chemical irregularities that affect the stone’s look and brilliance) in larger diamonds are easier to notice simply due to the stone’s size. This means that the bigger the diamond, the better the clarity grades should be.
  2. Because of the “breakpoints” in diamond prices around the 1-carat and 2-carat marks, some diamond cutters are prone to compromising with the stone’s cut just so they can get it over the line and make it more expensive or to keep it under the line and more affordable. This means that you should be extra careful when buying diamonds around the 1-carat and 2-carat marks.
  3. Bigger stones also have more noticeable color so you’ll have to go for a diamond that’s even higher on the color grade if it’s bigger.
  4. Lastly, keep in mind that carat weight =/= surface area. This means that, depending on their cuts, a heavier stone may look smaller than a lighter stone that has been cut to maximize its surface area. Some of the cuts with the largest surface areas for their carat weight are the oval, pear, marquise, and emerald cuts, but these don’t sparkle as much as a round diamond, which has a lot of its carat weight hidden under the surface.

Third C: Diamond Clarity

Clarity refers to how clear the stone looks or how devoid of any internal and surface inclusions and other problems it is. There are many types of flaws that can impact a diamond’s clarity grade.

These inclusions can be either chemical or physical in nature. Often, they are various fractures inside the stone that have happened either during its natural formation or they are man-made fractures that have happened during the mining or cutting process.

Diamond Blue Nile

An SI2 diamond with hard to spot flaws.

Click on the image and see the diamond from all angles here.

Other times, these inclusions are simply the presence of different chemical compounds or physical formations inside the stone. Another type of inclusions are the man-made “tunnels” that diamond cutters create to remove more obtrusive natural inclusions.

There are very few natural diamonds with no inclusions and a lot of them have only minor inclusions that are invisible or near-invisible to the naked eye. All these variations are neatly classified In the standard Diamond Clarity Scale used by most gemological institutes. It goes like this:

GIA Clarity scale explained
  • F and IFFlawless and Internally Flawless diamonds. These are the first two grades – as their names imply, these are rare and expensive diamonds with virtually no inclusions in them.
  • VVS1 and VVS2 – Very Very Slightly Included diamonds. These next two grades are for diamonds with only minute inclusions that are invisible to the naked eye and require at least 10x magnification to notice.
  • VS1 and VS2 – Very Slightly Included diamonds. These next two grades have more but still relatively minor inclusions that often still can’t be seen with a naked eye.
  • SI1 and SI2 – Slightly Include diamonds. These are the more affordable grades that, together with VS2, are often used for affordable mid-range jewelry purposes. SI1 and SI2 have inclusions that are easy to see with 10x magnification and can sometimes even be seen with the naked eye.
  • I1, I2, and I3 – Included diamonds. The I1 grade is also used relatively often for jewelry purposes but most vendors don’t offer I2 or I3 diamonds because they have too many inclusions.

The great secret of the diamond industry is that clarity is the least important of the 4Cs. Instead of getting hung up on the clarity grade, it’s better to inspect the diamond for flaws and ensure that it’s eye-clean. You can drop down on the clarity scale and find some amazing diamonds, while securing a great bargain. This is why you need HD imagery of the diamonds to make an informed choice.

Included diamonds

1 carat included diamonds at great prices.

Which would you choose?

Most people go for the VS2 to SI2 range of clarity grades as they offer the best compromise of eye-clean quality and affordable prices. However, you can still find great diamonds in the Included range at stunning prices.

The average 1 carat diamond is over $6000 but the diamonds featured above are around $2500. This is because of their lower clarity. Remember that once set in your ring, these diamonds will be the size of a pea or smaller, making their flaws even less noticeable.

Forth C: Diamond Color

The last of the 4Cs is Color. Color refers to whether the diamond’s lack of color and how pronounced any tints may be – the less noticeable such hues are, the better.

M grade diamond next to a H grade diamond.

Most retailers don’t sell below the K grade. See more diamonds here.

Keep in mind that here we’re talking strictly about colorless diamonds and the slight color in them. There is a whole separate category of rare natural fancy colored diamonds where the stronger the color is – the better. As far as colorless (or white) diamonds are concerned, however, color is undesirable.

Diamonds’ color hues are classified most commonly by the Gemological Institute of America GIA’s alphabetical diamond color scale which categories them like this:

Diamond color grading chart
  • D, E and F – the first three grades are for Colorless diamonds – stones with no noticeable color whatsoever.
  • G, H, I and J – these grades are Near Colorless and they do exhibit some barely noticeable color but nothing too impactful on the diamond’s look.
  • K, L and M – the next three are the Faint Color colorless diamonds. These stones have more pronounced color, usually yellow or brown, and aren’t considered “top range” for engagement rings.
  • N to R – these are the Very Light Color diamonds and aren’t recommended for engagement rings even if they are made from rose gold.
  • S to Z – these are Light Color diamonds and they are the transitional grades between colorless and colored diamonds. They are almost never recommended for engagement rings as they are neither good colorless diamonds nor good colored ones.

The color of colorless diamonds can come in several different tints but most commonly in yellow or brown. If you want to go for a diamond that’s lower on the color scale it’s smart to match the color of its hues with the ring’s metal – yellow tints go better with yellow gold and brown hues suit rose gold.

See how the metal impacts the two K diamonds below. The rose gold setting makes the K diamond look whiter while the white gold setting makes the K diamond look warmer.

k color diamond engagement ring with yellow gold

K Diamond in Rose Gold Setting. Check Price Here.

I color diamond with platinum ring

K Diamond in White Gold Setting. Check Price Here.

All in all, while getting a diamond with overly strong color will impact it’s look, clarity and brilliance. Color is something you can compromise with to a point.

The D, E and F grades are usually overkill price-wise so it’s best to avoid them and opt for Near Colorless diamonds. If you like warm tints, drop down as far as you feel comfortable on the color scale.

Diamond Certification

With the 4Cs out of the way, we thought we should mention the so-called “5th C” of jewelry diamonds – Certification.

Diamond certificate

GIA certificate for this round diamond. Check this diamond here.

This refers to the official certificates from prominent international gemological institutes that come with most diamonds. Institutes such as the GIA, the AGS, and others specialize in judging and certifying diamonds before they get to the store. This is crucial work as a diamond’s certificate doesn’t just tell the customer what they’ll be getting for their money but also proves the authenticity of the diamond. Keep in mind, however, that only certificates from reputable institutes such as the AGS and the GIA should be taken seriously.

With those quality-related certificates, we should also mention the Kimberley Process certificate which proves that the diamond has been mined from a conflict-free zone and buying it doesn’t contribute to any militant groups and bloody conflicts. “Conflict-free” is also often referred to as a 5th or 6th C with jewelry diamonds.


Girl wearing big round shape diamond engagement ring

This is not really a diamond attribute – but it’s essential if you want your diamond to look it’s best. There’s no point in buying the best diamond with the perfect combination of the 4Cs if you don’t keep it clean! When dirt, grime and grease get on a diamond, it diminishes it’s beauty and sparkle, making it appear like a lump of glass.

Keeping a diamond clean and free of dirt will make it appear to advantage, enhance its sparkle and make it look bigger than it is. And this is why we believe that cleanliness is the most important C!

Ready to start your search for high-quality diamonds? Click here to browse.

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