These four qualities of a diamond are the key components that impact its beauty and structure. The 4C’s interact with each other within the diamond. They dictate how the diamond appears and how high quality it is. As an example, the diamond’s ability to reflect light back to your eyes depends primarily on cut quality but also on colour and clarity. 

The four-diamond characteristics are graded by professionals on a consistent scale, giving you a tool to evaluate diamonds. By reviewing the 4C’s of a particular diamond, you can better determine if the diamond is of high-quality.

The GIA and the AGS are the prominent institutions with a sophisticated grading system for evaluating diamond characteristics. They are the most consistent entities and the ones we recommend gaining a diamond certificate from. Each of the C’s is graded on a scale and can be evaluated for quality. Though some universal terminology and standard grading exist, it does vary by lab entity.

Gradings of the 4 C’s help determine the value of a diamond and indicate its quality. Diamond sellers often set their prices based on grading reports. Knowing the basics of these gradings is helpful when comparing two similar diamonds, but what remains most important is how the diamond appears to the naked eye—and how attractive the diamond is overall. In this sense, having a foundational understanding of the 4 C’s is imperative as a buyer, so that you can avoid spending your budget on a component that will go unnoticed.

Without finding the right balance between the 4cs, you will end up overpaying for certain qualities of a diamond while not spending enough on others. Let’s say you are thinking of purchasing a one-carat diamond. If you ignore finding the right balance, you can end up with a cheap, yet incredibly ugly, diamond. Or you can think “only the best” and spend a boatload on this exquisite diamond. But if you follow our recommendations, you can find the perfect balance of quality and value like this diamond.

Why the 4Cs matter

When the diamond 4Cs was introduced in the mid-20th century, for the first time ever, the world had a universal standard for judging the quality of a diamond and a transparent way of determining its value. The 4Cs also became a tool for people to understand why they might want to buy one diamond over another when it was often hard to discern differences between two different diamonds with the naked eye.

The diamond 4Cs are still as important today as they’ve always been. However, a renewed emphasis on one of the Cs (cut) can help a diamond shine more brilliantly. Knowing this means you as a shopper can prioritize some Cs over others to find a diamond that works within your budget.


Of all the 4Cs, the diamond cut has the greatest effect on a diamond’s beauty. In determining the quality of the cut, the diamond grader evaluates the cutter’s skill in the fashioning of the diamond. The more precise the diamond is cut, the more captivating the diamond is to the eye.

A diamond’s cut is harder to quantify than colour, clarity and carat weight. That’s because cuts can vary from diamond to diamond and have to do with how the diamond cutter chooses to shape, facet and polish a diamond. Sometimes diamonds are cut, so they’re heavier, thus fetching more value for their carat weight; sometimes they’re cut to hide or minimize inclusions.

But many diamond companies are focused on cutting diamonds for beauty. A diamond is essentially a prism of light, and diamond cutters work to let the lightest shine through each stone. When done well, a diamond’s cut can be the most important C. When grading the cut of a diamond, laboratories evaluate the diamond’s


The colour of gem-quality diamonds occurs in many hues. In the range from colourless to light yellow or light brown. Colourless diamonds are the rarest. Other natural colours (blue, red, pink, for example) are known as “fancy,” and their colour grading is different from colourless white diamonds.

Diamond colours fall under a D-Z scale, with D meaning completely colourless (and the most expensive), and Z having a light yellow hue. According to Mills, standard diamond quality falls within the D-J colour grade. The shape of the diamond also influences its spot on the colour scale. A brilliant round diamond, for example, hides colour incredibly well, meaning you can go further down the scale without seeing any yellowing. However, longer diamond shapes, like oval and radiant, reveal colour much easier. Keep in mind, though, diamond colour is essentially personal preference and doesn’t indicate quality whatsoever.


Diamonds can have internal characteristics known as inclusions or external characteristics known as blemishes. Diamonds without inclusions or blemishes are rare; however, most characteristics can only be seen with magnification.

This C involves the number of natural imperfections, called inclusions, present in the diamond, and whether you can see them with the unaided eye—the GIA grading scale rates diamonds from Flawless (FL) to Included (I). However, a stone doesn’t have to be at the very top of the scale Flawless or Very Very Slightly Included (VVS) to look perfect and inclusion-free. It’s all about how eye-clean the diamond appears, and Mills says this is what usually surprises people most when viewing diamonds in person. In fact, if an SI1 (Slightly Included) clarity diamond appears perfectly eye-clean, there is no visible difference between a VVS1 (Very Very Slightly Included) clarity stone of the exact same carat, colour, and cut—minus about tens of thousands of dollars.


The carat is the diamond’s physical weight measured in metric carats. One carat equals 1/5 gram and is subdivided into 100 points. Carat weight is the most objective grade of the 4Cs.

People often mistake carats as a measurement of size, but they actually measure weight. Diamonds are also measured in points: 100 points equals 1 carat. The abbreviation “ctw” standards for “carat total weight,” which measures all diamonds’ total weight in a piece of jewellery.

Very small differences in carat weight can sometimes result in a disproportionate spread in cost. To the eye, the difference between a 1.1-carat and 1.2-carat diamond (1 1/10 carat and 1 1/5 carat diamond) might be impossible to discern, but the cost difference between those carat weights can be thousands of dollars for otherwise identical diamonds. If shaving off the cost on a diamond, start by looking at a diamond 10 or 15 points less than a diamond you like. For example, if you love a 1.20-carat (1 1/5 carat) diamond, see what it looks like next to a 1.10-carat (1 1/10 carat) diamond of the same quality — it’s likely you’ll have difficulty seeing a big difference, but you may save hundreds of dollars.

Why “Cut” Is The Most Important Of The 4 Cs

Diamond cut is the single most important of the 4Cs when it comes to the physical beauty of a diamond. Why? Because a diamond’s cut determines how much it sparkles. 

The number of facets, the angle of the facets, and the symmetry and alignment of the shape will affect how the diamond returns to the light. And the goal of diamond cut should always be optimal light return. However, because diamond crystals are among the most valuable items on the planet, most diamonds cut in the industry today are still cut for weight retention at the expense of beauty. We cut each and every one of our diamonds for optimal light return at Hearts On Fire. 

And as a result, Hearts On Fire diamonds always receive an Ideal rating from the American Gem Society (AGS). An Ideal rating from the AGS is rare—in fact, only about 3-5% of the world’s cut diamonds are cut to ideal proportions. Hearts On Fire diamonds are truly the best-of-the-best.

Achieving an Ideal cut involves both art and science, and neither should be sacrificed. For example, some diamond cutters tailor the cut, so the carat weight stays above 1.0 carats. But this isn’t always a good thing.

For each individual diamond, there are specific proportions that will make the diamond sparkle at its best, and it is far better to have an Ideal-cut diamond that is 0.90 carats than a poorly cut diamond that is 1.00 or 1.10 carats. A good cut will result in a better sparkle. That’s why cut is the most important of the 4Cs—if a diamond is poorly cut, no clarity grating, colour grading, or carat weight will make up for it. The diamond will look dull and glassy. When a diamond is cut to the proper proportions and symmetry, it will return light out of its top. If a diamond cut is too deep, the light will leak out the side, and if a diamond cut is too shallow, the light will escape out the bottom. Ultimately, the precision of the cut affects the value of a diamond by 50% or more. Next to carat weight in a larger diamond, it is the most important value factor for a diamond. 

What is the Best Grade for a Diamond?

The answer to the question of what is the best grade diamond is a D colour diamond with Flawless clarity and Excellent cut at the weight that you desire. There are additional attributes to consider such as no fluorescence, but when it comes to the 4 C’s this is it.

But that is the “ideal diamond”, the most expensive diamond there is. A “perfect” diamond.

Realistically, under a budget, the best grade would be a G colour diamond with si1 clarity grade and excellent cut with no fluorescence at a weight of your choice.

What are the 5 C’s of Diamonds?

I’m often asked what are the five C’s of diamonds? Technically speaking, there are no more C’s, only four. However, lately, there are other Criteria which people refer to as the Fifth C of Diamond Grading.

The fifth C is sometimes referenced as Certificate and sometimes as Confidence. It doesn’t matter which one you follow the intent behind it; the meaning is the same. Knowing what you are buying or in other words, get what you are paying for.

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 jewellery companies issued their own Certificate of authenticity for the diamond’s quality and attributes. But those companies have the incentive to lie (or at least to round it up) for their own sake. A minor “mistake” of grading a diamond colour as D instead of E means A LOT of money. Therefore, only trust the objective Certificate of a gemological institute and the GIA’s Certificate is known to be strict non-compromising and accurate. Why settle for anything else?

Four Steps to Diamond Buying

Step 1: Determine Your Budget

Before you even start shopping, you’ll need to set your budget. Diamonds are expensive, so a budget will ultimately help you decide what you want.

You probably already know that diamonds are expensive, but you might not know just how expensive they are. Keep in mind, though, that you can find a nice diamond within most budgets. However, you may have to compromise.

For example, lab-made diamonds are a nice alternative to mined diamonds. Although they have the same beauty and durability, they cost about 30% less. So, buying a lab-made diamond will save you some money.

Step 2: Pick a Diamond Shape

Next, figure out what shape best suits your style. Round brilliant diamonds are the most popular, but other shapes cost less. You have many choices: ovals, pears, squares, rectangles, and even triangles. Many diamond shapes even look larger than a round of the same carat weight.

The square shape of the princess cut is a very popular choice for engagement rings. © CustomMade. They are used with permission.

If you’re not sure which shape is best for you, check out our guide to diamond shapes.

Step 3: Find the Best Color and Clarity Grades for Your Ring

After you pick the shape, find the colour and clarity grades that will give you the best deal. You’ll probably want a diamond that appears colourless or white in the setting, rather than off-colour. You’ll also want a diamond that appears flawless to the eye from a normal viewing distance (about 6 inches away).

Colourless and flawless diamonds receive the best grades — and command the highest prices. Just remember, you’re looking for the grades that will get you the best deal. The colour grade you choose will depend on whether you want a ring made of yellow gold, rose gold, or white gold or platinum, as well as the shape and setting style you want. The clarity grade you pick will also depend on the diamond shape.


Step 4: Find the Best-Cut, Largest Diamond

Finally, it’s time to start browsing! By narrowing certain cut parameters, you’ll be able to find a diamond that’s extra sparkly. Then, you just find the sparkliest, biggest diamond within your budget.

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