Intro to Lab-Grown Diamonds: The Diamond 4Cs | 4cs 3

Intro to Lab-Grown Diamonds: The Diamond 4Cs

Last Updated on March 31, 2023 by LabGrownCarats

Read our intro to lab-grown diamonds to save you money and get a much better diamond (while being better for the environment and society!) We’ll teach you what you need to know before buying a lab-grown diamond in our easy guide to the lab-grown diamond 4Cs.

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The “Diamond 4Cs” is the globally recognized standard for evaluating diamond quality. They comprise the key features to look at when assessing and buying diamonds. The 4Cs are:

  • Carat: The weight of the diamond
  • Cut: The quality grade of the diamond cut
  • Color: The color grade (or tint) of the stone
  • Clarity: The clarity grade (clearness) of the stone

The 4Cs are graded and certified by independent evaluators. GIA (Gemological Institute of America) is the most well-known grader who invented the 4Cs, formally known as the International Diamond Grading System. Today, many reputable grading laboratories exist. However, the International Gemological Institute (IGI) is the leading laboratory for grading lab-grown diamonds, and you’ll often come across their grading certificates.

Each of the 4Cs is critical when evaluating a diamond. Understanding the significance of each will not only help you pick the perfect diamond but also save money. If you want to go through a step-by-step guide to finding the perfect diamonds, read our lab-grown diamond buying guide.

If you want to learn the basics of lab-grown diamonds, keep reading our intro to lab-grown diamonds.

Our 3 favorite diamond jewelers for lab-grown diamonds


We’ll start our intro to lab-grown diamonds with diamond carat, which is the most well-known of the 4Cs. Carat is a measure of weight, not size as many are led to believe. This is the diamond way of saying how heavy the stone is.

1 diamond carat is equal to 0.007 ounces or 0.2 grams. About the weight of a paper clip.

As mentioned, people often think of carat as the size of a stone. And while the two are indeed correlated, they also depend on the cut of the diamond, for example, the size of the “surface” versus the “bottom.”

When a diamond is set in jewelry, you only see the stone’s surface. But you don’t see the depth of the diamond. However, the depth of the diamond is a critical feature since it determines how the diamond reflects light. And, importantly, light reflection is what really matters diamond-wise.

As a rule of thumb, carat is what you would look for when determining how big the diamond stone is. Just be aware that it’s doesn’t give you the complete picture. Carat weight is a function of the size of the uncut “raw” stone, how efficient the cutting process has been, and the shape of the diamond.

Lab-grown diamond carat weight - Intro to Lab-Grown Diamonds

To learn more about lab-grown diamond carats and the importance of carats when you shop for diamonds, read our in-depth diamond carat guide.

Diamond carat buying tips

A lot of people aim for certain carat weights, say 0.5, 1.0, or 2.0. This is primarily a vanity decision that allows you to tell others you have a specific “size” diamond. Take advantage of this and get a stone that is just below these popular weights, for example, 0.96-0.99. The difference will not be noticeable, and you will save money or be able to upgrade on the diamond cut grade.


Diamond cut grade is the most critical factor when determining the quality of the stone, in particular when it comes to the “sparkle,” which is what makes diamonds so unique. The diamond cut should not be confused with diamond shapes. The shape determines whether the diamond is round, oval, or even heart-shaped.

The diamond cut is solely related to how well the diamond has been cut into whatever shape it should be. The most important aspect of the cut is how light is reflected. Diamond cuts are highly complex and constructed to reflect as much light as possible. This requires the stone to be cut in certain angles and that the depth-to-surface ratio, and other ratios, are just right. Not an easy task.

Diamond cut grade is the most important factor when determining the stone.

Before the diamond is cut, the stone is in its raw form. Like the final cut, the raw forms also differ. Particularly for mined diamonds, while the laboratory-creation process is a little more controlled and the raw form tends to vary slightly less. How well the diamond cut turns out depends on the size and shape of the raw stone. Basically, what does the diamond cutter have to work with.

Lab-grown diamond cut - Intro to Lab-Grown Diamonds

As the stone is cut to maximize reflection, more and more raw diamond is discarded. This hurts the carat weight. The cutter might also try to cut around inclusions to improve diamond clarity, which impacts the weight or quality of the cut. There is, therefore, often a trade-off between cut grade, clarity, and weight. Often carat weight or clarity suffer to obtain the best possible diamond cut.

This explains why a high-grade cut is more expensive. It not only requires hours of highly skilled labor but also compromises the weight of the finished diamond. Since the cut is independent of how the diamond was created, the diamond cut and what you pay for it are exactly the same for mined and lab-grown diamonds. That’s why diamonds will always be costly and hold value even as prices fall.

Diamond cut buying tip

Always, always, always maximize the cut grade of the stone you’re buying. Instead, compromise on color, clarity, or ideally carat. We recommend that you don’t go below the excellent or ideal cut.

Learn more about the diamond cut in our in-depth article on lab-grown diamond cut.

Diamond color

The name diamond color can be a bit misleading. It is actually the absence of color, or rather lack of tint, that matters. Naturally, as well as in the laboratory, the presence of gas (nitrogen) or structural imperfections can make the diamond appear tinted – typically yellow or brownish. This is the reason why not all, in fact, very few, diamonds are colorless – even if grown in a laboratory.

Diamond colors are graded between D and Z, with D being truly colorless and Z being clearly yellow or brownish in color.

A, B and C diamond color grades were consciously not included to avoid confusion with other existing (and now deprecated) color grading systems.

What you need to know about diamond color grades is that from the colorless “D” down to “G” and “H” and under some circumstances all the way to the “K” grade, the color imperfections will be unnoticeable. However, the price differences are noticeable. Between two adjacent colors (e.g., H->I), you likely will not be able to tell any difference. Colorless diamonds are extremely rare and, therefore, also costly. Unless money is no object, avoid them.

Further, the jewelry set that the stone will sit in also impacts color perception. For example, a gold or rose gold setting will emit some of its yellow colors and “pollute” the light reflected by the diamond. For this reason, you can compromise on color grade if the diamond will be near something colored.

The diamond color, in this case, is not to be confused with “fancy” colors. Fancy colors are, first of all, very rare and very expensive too. Except for in the laboratory, where fancy colored diamonds are easier to create. That’s why fancy colored diamonds often are lab-grown.

The fancy color is not related to the transparency or light-emitting qualities but the actual color of the stone, for example red, blue, or pink. To avoid (or maybe add) confusion, fancy colored diamonds have the color grade Z+ and a graded along a three-dimensional scale.

If you are looking for a fancy-colored diamond, then learn more in our guide to lab-grown diamond colors.

Diamond color buying tip

Since colorless diamonds are both extremely rare and expensive, and since the difference from lesser color grades is not noticeable in a natural light setting, go for at most the H color grade. (you will likely not subject your jewelry to a microscope inspection in a lab after you’ve purchased it anyway – and neither will anyone else.)

Like the classic round brilliant shape, some diamond shapes have an immense sparkle that will outshine colored light. With these, you can safely aim for an I or J color. And if set in gold or rose gold, search for a J or K color graded diamond. Spend your savings upgrading to a better diamond cut!

If you are shopping for a fancy-colored diamond, you have your work cut out for you, but we’ll help you out in our easy guide to diamond colors. Just note that color is king with fancy diamonds (not cut) and that you should exclusively buy at a seller who offers high-quality diamond images (like James Allen or Clean Origin).

Diamond clarity

The last of the 4Cs is diamond clarity. While it could be confused with color imperfections, clarity is actually about tiny internal inclusions trapped in the stone or surface blemishes. They appear like tiny cracks (internal) or scratches (external). Both mined, and lab-created diamonds have inclusions and blemishes. Even in the sterile laboratory environment, the growing process leads to imperfections, and flawless diamond clarity is, just like in nature, very rare. And rare equals expensive.

Diamonds are graded on a scale from flawless (F) to I3 (the worst). The grading is done by magnifying the diamond 10 times (in practice, often more) to inspect and determine the imperfections’ size, position, and severity. Certified grading laboratories carry out the process. It is critical to note that these flaws are only seen under 10X magnification by a highly trained grader. Therefore, except for the lowest graded diamonds (I1-3), most people will not be able to see any flaws.

Intro to Lab-Grown Diamonds and diamond grading

There are two problems with inclusions and blemishes. The first is that they detract from the cleanliness or look of the stone. However, as most flaws are impossible to see with the naked eye, this is less of a worry. Just stay clear of I-graded diamonds. Most gem-quality diamonds fall between the VVS and SI grades.

The other problem is that even tiny impurities that you cannot see can harm the diamond’s ability to reflect light and, therefore, its brilliance. However, as was the case with the diamond color, the cut quality matters much more than the clarity when it comes to the sparkle of a diamond.

If you want to dig deeper into lab-grown diamond clarity, then read our in-depth guide to lab-grown diamond clarity.

Diamond clarity buying tips

Flawless diamonds are rare and are not worth the considerable premium. Unless you’re buying diamonds for investment purposes, which we don’t think you should anyway. The same goes for the VVS1/2 grades. If you buy a round brilliant or similar brilliant-type diamond, you will most likely be fine with a VS1 (better) to SI2 (worse).

Grading is not a perfect science and relies on the skill of the particular grader and laboratory, which introduces variance in grading. The most important thing to do when considering diamond clarity is to inspect it yourself to see if the diamond is “eye clean.” That is, can you see any imperfections under the 10-20X magnifications that premium diamond sellers show on their websites? Make sure to take your time to inspect these HD images.

We recommend buying at Clean Origin, Ritani, and James Allen since they allow you to carry out a proper inspection – while also offering unmatched support where you can ask for unbiased (and uncommissioned) guidance. Read our Clean Origin review, review of Ritani, and James Allen lab-grown diamond review.

What is the most important C and how should I prioritize?

What is the most important diamond C, and how should I prioritize?

Choosing and prioritizing the diamond 4Cs come down to personal preference and how you plan to use the diamond. But in 99% of cases, you should prioritize diamond cut over everything else. Diamond color and clarity come next, often with color being a little more important. The least important diamond characteristic is the carat weight. Any diamond with the highest graded diamond cut will look better than a larger diamond with a poor cut. Diamonds are all about sparkle, which depends, primarily, on how well the diamond has been cut to reflect light.

In the end, it comes down to personal preference and how you will be using the diamond. That said, we strongly recommend the following order of importance.

Our recommendation, again, depends on your use case and if the price matters. Since it probably does matter, use the below as a rough guide but make sure to learn the basics of lab-grown diamond yourself.

  1. Diamond cut: Has by far the biggest impact on brilliance and in turn how big and impressive the diamond looks. The brilliance is the unique feature that makes diamonds special and probably the reason you’re looking for one in the first place. So choose excellent or ideal cut. Unless you’re buying a fancy-colored diamond. In that case color is king.
  2. Diamond color: You can safely downgrade to a G or H and even to a J or K with a brilliant cut when paired with a gold setting. However, the yellow tint should not be too obvious or distract from the diamond’s beauty.
  3. Diamond clarity: A very close third, clarity can potentially negatively impact the stones ability to reflect light and in turn its brilliance. However, you’ll likely suffice with a diamond between VSI1 or SI2 and should rather compromise on clarity than cut.
  4. Diamond carat: Often the C that people cares most about – but it really shouldn’t be. A large diamond with poor cut, color and clarity will appear much smaller than a higher grade but smaller stone. Just leave your vanity at the buying door. And buy a diamond just below the popular carat weights, you get the best deals on those.

Find the best deals on lab-grown diamonds

You can save even more than the 30-40% that lab-grown diamonds cost less than mined equivalents. How? Just follow our updated list of current deals and sales on lab-created diamonds and lab-diamond jewelry.

Need help?

When know that the task of buying lab-grown diamonds can be daunting. We are here to help you find the right diamond, the best place to shop or answer any questions you might have.