Diamond Essentials: The 4Cs & More

A guide to understanding your diamond’s characteristics and how they affect value.

Understanding a diamond’s 4Cs – cut, color, clarity, carat – and other important characteristics help provide clarity about your diamond and its true value. At Mondiamo, these characteristics are used as benchmarks by our gemologists and pricing team to help determine the value of your diamond.

We want you to feel empowered and confident when selling your diamond jewelry, so here are some important facts about the 4Cs, fluorescence, and fancy color diamonds, and how these unique attributes effect the value of your diamond.


Cut image

When talking about a diamond’s cut, we’re not speaking about its shape. Cut refers to how a diamond’s proportions – angles, symmetry, facet placement – interact with light, while shape describes the outline of the diamond, such as round, square (princess), or pear. Often a diamond with a higher cut grade will return light through the crown, creating sparkle and fire, while a diamond with a lower cut grade will appear dark or lifeless. It’s important to consider how well, or how poorly, a diamond is cut. Even within a particular cut grade, subtle differences in angles and proportions can significantly impact your diamond’s beauty, and therefore its value.


Color image

White diamonds are measured from D to Z on a color scale. Starting with colorless D, subtle differences in body color increase as you move towards Z. While variances in color are often invisible to the untrained eye, even the slightest hint of color can have an effect on a diamond’s value.


Clarity image

Flawless diamonds are very rare. Most diamonds have microscopic imperfections that are formed when the diamond is crystallized under the Earth’s crust. External imperfections are known as “blemishes” while internal imperfections are called “inclusions”. Diamonds with the fewest and smallest flaws receive higher clarity grades, so the closer your diamond is to flawless, the greater its value. Since the clarity grade of a diamond is determined under 10X magnification, most inclusions do not impact a diamond’s beauty in a significant way.


Carat image

Carat is often the most misunderstood of diamond’s 4Cs. Contrary to common belief, carat is a measurement of a diamond’s weight, not its size. Two diamonds can have the same carat weight, but depending on the diamonds’ proportions, one might appear larger than the other. It’s important to consider carat along with the other Cs when determining a diamond’s value.


Fluorescence image

Diamond fluorescence refers to the strength of a diamond’s reaction to long or short-wave ultraviolet light. A diamond with fluorescence will emit visible blue, yellow, green and even white light when exposed to UV rays, while a diamond without fluorescence will be unaffected. A diamond grading report will note the degree of fluorescence within a diamond – gradually growing from None, Faint, Medium, Strong up to Very Strong. For most diamonds, fluorescence does not have a noticeable effect on appearance day-to-day. However, some diamonds can appear milky, or cloudy, due to fluorescence and this will negatively impact the diamond’s value.


Fancy diamonds image

While white diamonds, which are graded from D to Z, decrease in value as color becomes more obvious, it’s the exact opposite for colored diamonds. Known as fancy color diamonds, the value of colored diamonds generally increases with the saturation of color. From red to purple, fancy color diamonds can occur in every color of the rainbow due to trace elements or structural defects within the crystal. Less saturated color is more common, but fancy intense and fancy vivid diamonds – those with strong and pure color – are extremely rare and very valuable. The value of a fancy color diamond is determined almost entirely by the hue, tone and saturation of color and for this reason, it is necessary for the diamond to be visually inspected in order for value to be determined.

Keep in mind that there’s no one “C” that is more important than the other. To properly value a diamond, the 4Cs along with other attributes such as fluorescence, fire & beauty should always be taken into consideration. That is why Mondiamo visually inspects all diamonds at our evaluation center to look for additional ways to add value to your final offer. You can learn more about how Mondiamo values your diamond by watching the video on Our Process page.

Of course, you can always rely on the expertise of our gemologists to better understand diamonds, so don’t hesitate to call, text or email if you have any questions. We’re here to help!