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Carat Weight: What Does Carat Measure In Diamonds?

Carat Weight: What Does Carat Measure In Diamonds?

When you start looking to buy a diamond engagement ring, you become accustomed to hearing about cut, clarity, color, and carat. While these all define crucial aspects of a diamond, the carat is the one that many consumers pay close attention to when making their choice.

But what does carat measure in diamonds?

A “carat” is, simply put, a measurement of weight in diamonds. Not to be confused with “karat” – which is a measurement for purity of gold, by the way. 

How does the carat weight affect the price of a diamond? What are the other factors that impact the diamond’s price?

In this article, we discuss these – and many more – questions, so be sure to read until the end!

What Is Diamond Carat?

As we explained already, a diamond carat refers to the diamond’s weight – and one metric carat equals 200 milligrams. It’s related to the size of the stone, too – but the carat weight and size of the diamond aren’t the same: 

Two gemstones with the same carat weight and shape can look very different depending on the cut.

The Importance Of Diamond Carat

How vital a diamond carat is will mostly be a matter of subjective opinion. But what carat weight really impacts is the price of the stone. 

In that sense, carat weight is often the single most crucial factor of the 4C’s used in evaluating the price of the diamond. Don’t worry; we’ll cover the rest of the C’s later on in this guide.

With that being said, diamond carat is as vital as you want it to be. 

If you’re looking for a larger diamond, then yes, carat weight might be the number one priority for you. Those who don’t feel that a bigger stone is necessary may find other diamond factors – such as clarity, for example – are more important.

Related Read: 4 Cs Of Diamonds – Order Of Importance: The Most Important C?

How Carat Affects The Price Of A Diamond

In general, the higher the carat weight is, the higher the price of a diamond is. If all else is equal, the price of a diamond increases with carat weight.


Well, larger stones are harder to come across and are, thus, more desirable.

However, two gems of the same carat weight can have different values depending on other aspects – cut, color, and clarity.

In other words, carat weight will indeed have a meaningful impact on the diamond’s cost, but it’s not the only determining element in the price.

You could have a precious stone with high carat weight, but if it’s poorly cut, or if the clarity isn’t that good, the price of the diamond will go down rather than up.

How Carat Weight Impacts The Size Of A Diamond

Many people think that a diamond carat is the same as a diamond size. That’s completely false, though. 

The diamond carat weight refers to the mass of the stone, whereas the size is just physical size, and the cut can influence it more than the actual carat weight.

Believe it or not, a diamond with higher carat weight and poor cut can still appear smaller than a diamond with lower carat weight and better cut.

For instance, a 1-carat round brilliant cut diamond isn’t half the size of a 2-carat stone. A 1-carat round brilliant will average 6.4 millimeters in diameter, while a 2-carat will average 8 millimeters – bigger but not twice as big. 

That’s why we stress the importance of not discounting smaller carat weight.

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How Diamond Carat Is Weighed

Jewelers use precise scales to measure diamonds’ carat weight, and the process is relatively straightforward. Seriously, a highly calibrated scale that’s capable of measuring small weight is all you need. 

Diamond-grading labs – such as the GIA or AGS, for example – will have these highly accurate scales.

The Carat Point System

Jewelers commonly use a point system when discussing diamond carat weights – but that isn’t something that’s often expressed to customers. Still, it’s helpful to know about the point system if it ever comes up in conversation with your jeweler.

So, here’s a quick explanation: Within the diamond industry, people will refer to a diamond as having “X number of points.” That refers to the fact that carat weight equals 100 points – each point is 0.01 carats

So, a “95 pointer” is another way of saying a “0.95-carat diamond.”

Related Read: Can You Measure Diamond Weight In Grams?

Money-Saving Tips

Many consumers tend to make carat weight their top priority since many feel that higher carat weight is automatically more impressive. 

There’s nothing wrong with striving for the higher carat weight. However, it’s essential to know that bigger doesn’t always mean better.

You’ll find that the highest quality stones are exceptional in all of the 4C’s – and not just the carat weight.

Our point is, don’t ignore cut, color, and clarity just so that you can get a diamond with a higher carat weight. That could lead to purchasing a gem with hidden inclusions, a dull appearance, or poor color.

In addition, you can also try looking for diamonds with slightly lower carat weight for a lower price point. The difference between 0.95-carat and 1-carat diamond is indistinguishable to the naked eye – but can make a considerable difference in price.

The so-called “magic sizes” are especially popular, thus more expensive. For instance, a 2-carat stone can be drastically more expensive than a 1.90-carat gem similar in looks.

Suppose you really want a gem with a higher carat weight – but you’re on a budget. In that case, we’d recommend opting for a diamond with a more prominent face, such as a round brilliant cut, which looks bigger than most diamond shapes due to its weight distribution.

And if you’re ready to trade cut for carat weight, you should select a shape that’s more forgiving on the diamond’s quality – at least to the naked eye.

For example, an emerald diamond belongs to the step-cut family and features fewer facets than a round brilliant-cut gem. That allows any imperfections within the diamond to be noticed much easier with the naked eye.

You could still choose an emerald diamond with higher carat weight and go for the slightly lower clarity because it will lower the cost of the stone – without being too obvious.

If you’re going to prioritize carat weight over any other C, don’t be afraid to keep an open mind – and let your jeweler hand-select some stones.

Related Read: How Can You Tell The Size of A Diamond?

Other Factors That Affect Diamond’s Price

To ensure you get the best value for your money, we’ll highlight other vital factors that impact a diamond’s price – apart from carat weight, of course.

Diamond’s Cut

The cut of a diamond is by far the most crucial aspect to consider when purchasing a diamond – and whatever compromises you make with other elements are worth it.

Here’s why: The cut defines a diamond’s scintillation, sparkle, fire, and overall brilliance. The ideal diamond cut can produce a sparkle that can hide any inclusions within the gemstone and mask undesirable colors, making an average stone look like a top-quality graded one.

But don’t confuse cut with the shape of the diamond: 

The cut is the proportion, symmetry, and polish, and the shape of the stone is the outline shape from the top down. For instance, the “round” in “round brilliant” is a shape and not the cut.

The cut determines how brilliant and sparkly a diamond is and defines how light traverses through each of the stone’s facets. 

A bad diamond cut will leak light, leading to a dull appearance. An ideal cut has perfect proportion and symmetry. Facets are purposefully cut to maximize the light’s reflection.

Aesthetically speaking, a diamond’s cut significantly affects the stone’s beauty – the better the cut, the more sparkly the diamond is. Since the cut is a higher priority, we recommend getting the best cut you can for your stone. 

You can save some money by scaling down on other C’s when you have a perfect cut. 

Diamond’s Color

The diamond color also has a significant impact on the overall appearance. 

It’s the yellow hue in a diamond, and it’s graded on a scale from D to Z. However, most retail jewelry shops don’t sell stones with a higher color grade than K.

Colorless diamonds are extremely hard to come across and generally come at a premium price. Most stones have a slight yellow tint – one which you can’t detect with the naked eye:

It’s rather challenging to tell an utterly colorless stone from a nearly colorless one. That implies that there’s no point in spending your money on something with no detectable difference.

To get the best value for your budget, you should consider opting for color G, which is usually viewed as the inflection point between a colorless diamond and a slightly noticeable tint in the gem. 

But again, most people can barely tell the difference between the two.

Color G is a safe bet, but it’s still acceptable to have a diamond with color grades of H or I and an excellent cut – much more than a fair grade cut stone with the color F.

Related Read: Diamond Color Vs. Clarity: What’s More Important?

Diamond’s Clarity

Diamond’s clarity describes the flaws within the diamond. These flaws consist of two types – inclusions, which are internal flaws, and blemishes, which are flaws on the diamond’s surface. 

Almost all diamonds have flaws, but what matters is the visibility and location of these flaws. People usually make the mistake of assuming that all high-clarity diamonds are eye-clean.

Labs will grade the clarity of diamonds based on visible inclusions under an x10 magnification. No human eye can detect these flaws in such detail. 

An imperfection would have to be evident to be easily detectable by a casual viewer.

Even if you purchase a stone with the highest clarity grade, there’s a chance you won’t be able to appreciate it since it’s invisible to the naked eye. 

With that said, a clarity grade of VS2 might be the safest bet. 

For example, if you look at differences in price between different clarity grades with identical cut, carat weight, and color, you would notice that flawless diamonds are priced much higher – since they’re rarer.

However, it’s almost impossible to appreciate high clarity in a diamond due to the difference not being visible to the naked eye.

Keep in mind that diamonds with identical 4C’s can differ in pricing significantly. That’s related to the type of flaw and its visibility: 

For instance, there are SI2 stones that are eye-clean, while others have unappealing clouds or giant black crystals within them.


A certification from a reputable lab such as GIA or AGS is another crucial factor in determining the diamond’s price. 

First and foremost, certification will inform the consumer that the stone is a genuine diamond or not. With a grading report, consumers can confirm the quality of the diamond from an unbiased third party.

Why don’t companies offer a certificate sometimes? It’s not too common to come across a certificate for a diamond with a clarity grade of I1. 

Well-established companies rarely sell diamonds with an I1 clarity grade issued by the GIA and assume that they’re able to sell such stones at the same or higher prices without the certificate.

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Diamond Fluorescence

Diamond fluorescence is the soft blue glow that a diamond emits under a blacklight. This visual effect is natural in about 33% of all diamonds found on the global market.

Often, the fluorescence doesn’t negatively impact the diamond – and sometimes, fluorescence can help you – especially when looking at G-J colors.

Blue fluorescence can counteract any yellow tints that lower graded stones might have. Thus, it can improve the stone’s overall appearance with a G color grade or lower.

On the other hand, fluorescence could also be yellow or green – these types of fluorescence will always lower the price of a diamond unless the stone is a fancy green or yellow. In such a case, this fluorescence will make the stone appear more saturated, therefore, enhancing its value.

Generally, fluorescence decreases the value of diamonds with color grades of D to F, though it might not impact the price of diamonds with color grades from I to J.

Medium to strong blue fluorescence can lead to stone appearing milky, decreasing its value.

Related Read: What Are The Characteristics Of A Diamond?

Bottom Line

So, what does carat measure in a diamond? 

Carat is a weight measurement in diamonds, and 1 carat equals 200 milligrams. Carat weight is related to the size of the stone, but it’s not always the case that the bigger diamond has a higher carat weight.

Even though diamonds are generally priced per carat, there are other factors to consider when shopping for a diamond, such as cut, color, and clarity. 

Try to find the right balance of these aspects; that’s how you get the perfect stone.

Related Read: How Many Carat Diamond Should You Wear?