

When shopping for a diamond, there are so many things to consider that walking into a jewelry store can be quite intimidating if you have absolutely no idea what to look for. When most people walk into a jewelry store, they’ll most likely be focused on two metrics: carat weight and diamond size. Inexperienced shoppers might mistakenly believe that these are the same thing.
While each of these plays an essential role in the value of a diamond, it’s crucial to have a good understanding of each before you go shopping. By the end of this article, you should have a thorough understanding of the differences between the carat weight and size of a diamond.
What Is Carat Weight?
The carat system that we all have come to know weighs exactly .200 grams or .00705 ounces. While the imperial system is the most widely used measuring system in the United States, you’ll notice that jewelers typically stick to using the metric system. There are two reasons for this. The first is that the metric weight of a carat provides a much rounder unit of measurement. Secondly, the metric system is the standard measuring system used by jewelers worldwide.
Here’s a short history lesson on the carat. The word carat is actually derived from similar measurements going back all the way to the ancient Greeks. And while it has had quite the etymological journey, the word entered the English language nearly 600 years ago.
Despite its enduring use in the English language, the carat that we use today was formally standardized in the early 1900s at the 4th General Conference on Weights and Measurements. This conference is held by the International Bureau of Weights and Measurements and takes place every four years in Paris, France.
Prior to the Bureau’s standardization of carat weight, a 1-carat diamond could be heavier or lighter than .200 grams depending on what country the diamond was coming from. As you can imagine, the standardization of the carat caused quite a stir as the value of jewelers’ diamonds instantly changed as new laws governing measurements went into effect. While some countries like France made these legal changes immediately, others like the United Kingdom were slower to adopt the change into their legal frameworks.
The largest diamond ever found weighed over 3100 carats (621.35 grams or 1.33 pounds) and is known as The Cullinan. It was cut into several diamonds of varying sizes, the largest of which are displayed among the Crown Jewels of England.
How Is The Carat Weight Used?
As previously stated, 1 carat is equal to .200 grams. Diamonds can be found in just about any carat size, but between 1 and 2 carats are among the most popular. A diamond’s weight can also be referred to as “points.” One point is equal to 1/100th of a carat. If the point system is being used, it’s typically for diamonds under 1 carat. So a diamond weighing .25 carats may be referred to as a 25-point diamond.
When shopping for a diamond, it’s also important to note that the value of the diamond does not scale linearly with its size. As a diamond reaches a heavier weight, its price goes up exponentially.
Novice diamond shoppers should also be cognizant of the fact that a diamond’s carat weight is not the only, or even most important, factor in determining its price. There are four criteria, collectively known as the 4C’s, that determine a diamond’s value: diamond cut, diamond color, diamond clarity, and diamond carat weight. So you can find two diamonds with the exact same carat weight, but they will have vastly different prices depending on their cut, clarity, and color.
When you’re out there looking for the perfect diamond for your engagement or wedding ring, remember that no two stones are the same, and consulting with an experienced jeweler is your best bet for finding the perfect diamond.
What Role Does A Diamond’s Size Play?
The “size” of a diamond is a bit of a misnomer. When you think of a diamond’s size, you’re probably thinking of how large it looks when looking directly at the face. There are a variety of factors that can play into the perceived size of a diamond. More specifically, the shape and cut of a diamond will impact how big the stone looks. When shopping, however, size isn’t a great way to determine value. You can have a stone that looks larger but has a shape or cut that makes it undesirable.
The Anatomy Of A Diamond
When we’re talking about a diamond’s size, we’re looking at more than just its width, length, and depth. There are a number of different measurements that are looked at, and each can have a dramatic effect on a diamond’s performance—that is, its brilliance. The Gemological Institute of America provides an excellent overview of the diamond’s entire anatomy. We’ll provide a cursory overview here.
Table
The table is the topmost facet of a diamond.
Cutlet
The cutlet is the bottommost facet of a diamond.
Crown
The crown is the top angle of a diamond that extends from the table to the upper portion of the girdle.
Pavilion
The pavilion is the bottom angle of a diamond that extends from the lower portion of the girdle to the cutlet.
Girdle
The girdle is a thin layer of stone that separates the crown of a diamond from the pavilion.
Depth
The total depth of a diamond consists of two different measurements. The crown height of a diamond refers to the depth from the table to the girdle. The pavilion depth refers to the measurement from the girdle to the cutlet.
Diamond Cut
When it comes to diamond size, the cut is equally as important, if not more important, than its shape. As we discussed earlier, a diamond’s cut is one of the 4C’s that determine its quality and value. The cut of a diamond can have a dramatic effect on how light travels through the diamond and reflects back to the eye. If a diamond is cut well, the light will have a brilliant sparkle when you look at it.
On the other hand, if a diamond is cut poorly, the light can leak out the sides, and the stone will not have the desired sparkle. This can leave the diamond looking lightless. No matter how heavy the carat weight, a poorly-cut and lifeless diamond will be an undesirable one.
Going back to the anatomy of a diamond, the measurements of the various parts of a diamond play a vital role in determining how light travels through the diamond. For each part of the diamond, there are a set of ideal proportions that determine its grade.
The Gemological Institute of America has set 5 cut grades that help determine a diamond’s value. The GIA’s 5 grades range from excellent to poor. The GIA also notes that there isn’t a single set of proportions that delivers an excellent cut for every single diamond. There are a variety of factors taken into account to determine what the ideal proportions are for any particular stone, and a rating is given accordingly.
Diamond Shape
The diamond’s shape can also have a dramatic effect on its perceived size and value. You might think that a diamond cut into a larger shape will cost more money, but that isn’t necessarily the case.
If you compare an oval-shaped diamond to a round-shaped diamond of the same carat weight, the oval shape will appear larger because of its elongated face. Assuming that these two diamonds are also the same color and have the same level of clarity, the larger-looking oval diamond will typically be cheaper than the smaller-looking round diamond.
Why? Because the round-shaped diamond is not only more sought after but takes more raw material to make.
The shape of the diamond can play a significant role in how large or small a diamond appears, and it can also have an impact on the diamond’s price!
Another good example is the heart-shaped diamond. These are less desirable because they are significantly more challenging to cut, and their complexity makes them more expensive to purchase than other shapes.
The most common diamond shapes include the round, oval, pear, emerald, princess, and Asscher shapes. Each has its own unique qualities that make it more or less attractive to buyers.
Finding The Perfect Diamond
Finding the perfect diamond can be a difficult endeavor. Even once you’ve figured out your ideal shape and carat weight, finding a diamond with the right level of clarity, brilliance, and color can take time. Going through this process alone can be quite stressful, even for the most experienced jewelry shopper.
Thankfully, you don’t have to go through it alone.
If you want to make the diamond shopping experience much easier and more enjoyable, LeoDaniels is here to help.
Our complimentary jewelry concierges are ready to help you find a diamond that you and your significant other will love.
If you’re ready to take the next step in finding the perfect diamond for your engagement or wedding ring, schedule an appointment, and our experienced jewelers will help you through the process.