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4 cs of gemstones

4 Cs of Gemstones

It’s no surprise that gemstones can be really valuable, but where does that value come from, and who decides that value? So, let’s talk about the factors that determine the value of a gemstone. You hear a lot about the 4 Cs of gemstones valuation. These are carat, color, clarity, and cut. Let’s go over what these mean.

What Are The 4 Cs of Gemstones?


Carat is one of the 4 Cs of gemstones, it is the weight of a stone. One carat is equal to a fifth of a gram, and there are 100 points in a carat. Remember, however, that carat weight does not equal size. Gemstones have different densities, so two gemstones of the same carat weight can be different sizes.

Take, for example, a one-carat round brilliant diamond. That’s going to be about six and a half millimeters in diameter. But a six and a half millimeter amethyst of the same cut will only be about 0.8 carats or 80 points because the amethyst is less dense.


Next, let’s talk about color. Color is a combination of hue, saturation, and tone, and every gemstone has an ideal color that gem dealers are looking for.

Hue is going to be the base body color of a stone, so think red, yellow, green, or blue. Saturation is how much of that hue is present. For example, a low-saturated red stone can start to look a little brown, and a low-saturated blue stone can look almost grayish.

The tone is how light or dark the hue is in the gemstone. Take amethyst, for example. A light-tone amethyst can be pastel purple like on the outside of the specimen, and on the inside, you have a mid-tone amethyst. But amethyst can be even darker, and a very dark tone amethyst can look almost black. Now remember that optical phenomena such as color shift or color change can also affect the value of a stone.


Clarity is another one of the 4 Cs of gemstones. It is the degree of transparency of a gemstone. It can be affected by internal inclusions or external blemishes.

Now, inclusions can be things such as minerals, gas bubbles, water fractures, or even bugs. If you’ve ever shopped for a diamond, you’ve probably heard terms such as flawless or VS, which means very slightly included. This is a grading that reflects the amount of inclusions visible under 10 times magnification.

Generally, the clearer the stone, the more valuable. This is especially true for colorless stones because inclusions can be quite obvious.


Cuts is one of the 4 Cs of gemstones. The cut of a gemstone can dramatically alter its appearance, but not every stone should be cut in the same way.

Colorless stones should be cut in a way that maximizes the amount of light transmitted through the stone, making them appear brighter. Colored stones, on the other hand, should be cut in a way that enhances their natural color.

Typically, uniformity and symmetry are more valuable in cuts; however, an exception to this would be fantasy cuts, which take a more artistic approach to lapidary. Let us know if you’d like a video all about fantasy cuts.

Other Factors That Determine A Gem’s Value

There are other factors that can determine a gem’s value as well. The rarer a gem is, for example, the higher its value. Optical phenomena such as chatoyancy or asterism can also make a gem more desirable. Typically, the fewer treatments a gem undergoes, the more value it has. Lastly, natural gemstones are going to command a higher price than their synthetic counterparts.

How Do Appraisers Determine the Value of a Gemstone?

Appraisers will take all of these factors into consideration when determining the value of a gemstone, and there’s a lot of subjectivity and nuance when it comes to gemstone evaluation.

Take a light red stone, for example. One appraiser could call that a ruby, but another lab will call it a pink sapphire, and the value of that stone will change depending on its classification.

It’s important to remember that a gemstone appraisal is not the same value as its selling price, and keep in mind that the value of a gemstone is subjective. It’ll fluctuate a lot with market demand. So, whether you’re buying or selling, it’s important to make sure that you get an appraisal from a trusted source.

We hope this article answered some of your questions about how gems get their value.

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