The 4Cs of Diamonds

Learn how to evaluate a diamond based on four key characteristics. As you explore engagement rings, you’ve probably heard the phrase “the four Cs.” This phrase refers to the four qualities used to describe a diamond—cut, color, clarity and carat.

The 4Cs also determine the diamond’s worth. Each quality is graded on a scale and should be considered in relation to one another when evaluating a diamond. Why? Because you can often “slide” up or down the scale on one quality to balance out another and still come away with an absolutely gorgeous diamond that doesn’t break the bank. In other words, a diamond doesn’t have to be at the very top of all 4Cs to be the right choice for your engagement ring. We’ll explain below.


People often assume a diamond’s cut is synonymous with its shape, but that’s actually incorrect. The cut of a diamond refers to how well the stone was faceted, proportioned and polished, and it’s the only quality not influenced by nature. Only precise craftsmanship and artistry can affect a diamond’s cut. It’s the most important of the 4Cs because it determines how a diamond interacts with light—meaning how much it ultimately sparkles. For this reason, the cut has the greatest influence on the appearance of a diamond.

When determining the grade of a diamond’s cut, experts evaluate three light-reflecting qualities. The first three are: 


Internal and external white light reflected from a diamond.


The scattering of white light into a rainbow’s spectrum of colors.


The flashes of light, or sparkle, a diamond produces.

In total, a diamond’s brightness, fire and scintillation are often referred to as a diamond’s “brilliance,” the diamond’s overall ability to return light to your eye.

Diamond cuts are graded as Excellent, Very Good, Good, Fair, and Poor. We suggest purchasing a diamond that’s graded either Excellent or Very Good for your engagement ring. A well-cut diamond will be stunning and bright almost regardless of color or clarity, whereas a colorless, perfectly clear diamond will appear dull and lifeless if it’s cut poorly.


The second most important quality to look at when considering a diamond is its color rating. The highest quality diamonds actually have an absence of color, whereas lower quality diamonds have a pale yellow hue to them. 

Diamonds are graded on a scale D-Z, and each letter grade represents a range of color 

  • D, E, F → Colorless and the most expensive.
  • G, H, I, J → Near Colorless 
  • K, L, M → Faint yellow hue may be slightly noticeable.
  • N - R → Very light yellow hue may be noticeable.
  • S - Z → Light yellow hue will be noticeable. Brown tint may also be noticeable.

Colorless or near colorless diamonds are recommended for engagement rings, as the less color a diamond has, the brighter the light passing through it will appear. 

However, it’s important to keep the diamond’s shape in mind as well when considering it color grade.  A round brilliant diamond can hide color imperfections more easily than an elongated shape, like an oval, pear or radiant. For these shapes, a higher color grade might be necessary to avoid a noticeable tinge.


The third C refers to the natural imperfections within a diamond or on its surface. Most of 

these inclusions or blemishes are impossible to see with the naked eye, though diamonds with the least amount of these imperfections are rated the highest on the clarity grading scale.

Diamonds are graded from FL (flawless) to I (included), and although we recommend choosing a highly rated diamond, it’s most important that the diamond appears “eye clean” — regardless of its actual rating. 

  • FL → Flawless
  • IF → Internally flawless
  • VVS1 / VVS2 → Very, very slightly included
  • VS1 / VS2 → Very slightly included
  • SI1 / SI 2 → Slightly included
  • I1 / I2 / I3 → Included 

This is where the balance of the 4Cs comes in. You can choose a diamond that’s higher on the color scale but lower on the clarity scale (as long as there are no eye-visible inclusions) to save money without sacrificing quality or beauty. 

Clarity is also more important for some diamond shapes than others. For instance, asscher or emerald-shaped diamonds require a higher grade of clarity to look most their very best due to their glassy, smooth tops.


The last of the 4Cs is carat, which is used to describe the actual weight of a diamond. 

One carat is equal to 200 milligrams. The more carats the diamond has, the most expensive it is.However, a diamond’s carat doesn’t actually refer to its size, as it’s commonly mistaken. In fact, two diamonds that have the same exact amount of carats can look radically different in size due to their other Cs—cut, color and clarity—as well as their shapes. Elongated shapes, such as ovals, pears or marquise, can appear larger than their carat weight.