Understanding What Diamond Carat Really Means

Understanding What Diamond Carat Really Means

What you may not know (and need to know!) about diamond carat weight.

If you are currently searching for the lab-grown diamond engagement ring of your dreams, you’ve probably encountered the “4C’s of diamonds” at one point or another. Because a lab-grown diamond is a real diamond, it has all the same physical, chemical, and optical properties as a natural diamond. That means balancing the 4C’s is just as important in selecting your dream lab-grown diamond! 

The 4C’s of Diamonds are: 

Cut, Color, Clarity, and Carat. 

Each of these qualities will influence the rarity, quality, and cost of a diamond. While each of the 4C’s is important, each person will value these characteristics differently. What matters most to one person may not be as important to another! 
This is why it’s so important to understand each of the 4C’s so you can decide for yourself!

The most misunderstood of the 4C’s of diamonds? 


Don’t get me wrong, carat IS important and tells us a lot about the value and rarity of a diamond. But it’s a diamond quality that is commonly confused by consumers! It’s time we bust a few carat-related myths before you buy your diamond!

In this post, we’ll dig into what a carat actually is, what matters most when it comes to choosing the carat weight of your diamond, and some of my favorite insider tricks to help you weigh your options so you can confidently select your most perfect diamond engagement ring.

#1 Carat is a weight, not a size

Believe it or not, a diamond’s carat doesn’t necessarily indicate the diamond’s size. Carat (abbreviated as ct.) is a measurement of weight! Although it may seem logical to equate size with weight, the two don’t always match up!

So what is a carat? 

One carat is about ⅕ of a gram of 0.20 grams.
While you can measure the length and width of a diamond in millimeters (this will determine its shape), jewelers measure the overall weight of a diamond in carats rather than ounces or grams. 

You may stumble across the abbreviation “tw” or “ctw” when shopping for diamonds. If you've ever wondered what “tw” or “ctw” stands for, it represents the total weight of the diamond or the diamond’s total carat weight.  For example, if there are side stones or a pave halo, the total carat weight (TW or CTW) will add up to the weight of all diamonds in the setting.

The metric carat is divided into 100 points and can be compared to pennies and dollars! A carat is represented by a whole number, such as 1.0 or 2.0. If a diamond’s carat weight falls in between whole numbers, these are called points and are represented as decimals such as .52 points. A two-and-a-half carat diamond would be written as 2.50 ct. 

Insider tip: Ever wonder what the difference is between carat and karat? It’s common to confuse carat and karat, but they’re not the same! In the U.S. and many other places, karat is the term used to measure the fineness of gold! In the U.K., carat is the term used for BOTH gems and gold!

# 2 All Carat Weights Are NOT Created Equal

Clients often come to me looking for “a 1.5 or 2 carat diamond” because we’ve come to associate carat weight with worth and, incorrectly, size.
What I tell my clients next usually surprises them:

“What if I told you I could show you a lower carat diamond that appears larger than a higher carat weight diamond?”

They often think I’m kidding, but I am not!

You see, what’s interesting is if I show you an oval, a round, and an emerald cut diamond with the exact same carat weight, they are going to vary somewhat significantly in shape and in size! 

Some will appear much larger than others even though they have almost exactly the same carat weight.

How could this be?

Some diamond shapes will appear larger per carat, while others will naturally look smaller per carat. These discrepancies are caused by how the carat weight is distributed across the entire stone AND the measurements of the diamond itself.  Hint! Weight is also dispersed in the depth of the stone!

Moral of the story: just because a diamond weighs more doesn’t mean it will look bigger!

Even three oval diamonds will have different length-to-width ratios depending on how elongated or wide and chubby they are. Carat weight can look different in each of these diamonds despite their similar shape! 

I share this with my clients and you to demonstrate that while carat weight may be noteworthy, it shouldn’t be the only aspect you consider if size is important to you! If you are actually looking to optimize the size and visual scale of your diamond, carat may not be the most significant quality to look for (instead, consider the diamond’s dimensions, cut, or your setting)! 

# 3 Magic Carat Weights

Despite the many misconceptions about carat weight, one thing you’ve probably heard (or simply noticed while shopping) remains true: Carat weight has the most significant impact on the overall cost of your diamond. 
The higher the carat weight, the more rare and valuable it is. 
When it comes to carat weight, the weight tells us more about the value and rarity of the diamond than it does about the size of the diamond. 
Furthermore, certain carat weights will spike diamond prices even if the differences are seemingly indistinguishable from one stone to another. 
These are called “magic sizes” (yes, even though we’re referring to the carat WEIGHT and not the SIZE). Magic sizes include carat weights like 0.25ct., 0.5 ct., 1.0 ct., and 2.0 ct. These “clean” numbers hold significance and even symbolism for many shoppers. 

That’s because the higher the carat weight of a lab-grown diamond, the rarer it is, and diamond prices are significantly influenced by rarity and exclusivity.
When buying your diamond, be sure it’s being accurately weighed within two decimal points. A 0.99 and a 1.0 diamond carat weight are NOT the same, and the price will (and should) reflect the discrepancy in total weight. Diamonds that hit the “magic” carat weight numbers will often sell at premium prices. 

Insider Tip: If you’re okay with a stone that has a slightly lower carat weight (i.e., 0.99 instead of 1.0), you may be able to save money without a noticeable difference in your stone. Or, you may choose to focus more on the brilliance of your diamond instead and invest in a stone with a higher clarity or cut grade.

Let’s Go Beyond The 4C’s

There is so much more to the diamond selection process than meets the eye. Luckily, you don’t have to navigate the journey alone. Whether you design a custom engagement ring with us or find your dream ring elsewhere, we feel privileged to be a part of your journey. Our goal is to guide you through the process so you can select a high-quality diamond that fits your style and budget as if we were sitting beside you in our NYC design studio! 

We take the time to teach you what you need to know beyond the 4C’s. That’s because we wholeheartedly believe that everyone should have access to reliable, transparent information so they can focus on what matters most to them and ultimately feel assured in their diamond investment.

If you’d like to schedule an in-person or virtual design consultation, we’d be thrilled to be a bigger part of your custom diamond ring journey. Click here to inquire, and we’ll be in touch to help you design your dream ring!

Previous Article Next Article