Carat Weight: Everything You Need To Know Before You Buy

Carat Weight: Everything You Need To Know Before You Buy

There are numerous ways to quantify a gem’s value. Whether you go off of the physical appearance or have a licensed gemologist take a closer look, the possibilities are endless. This can make the process a bit confusing for some consumers.

At Mark Henry Jewelry, we want to bridge the gap between retailer and customer. It is our job to make sure our buyers are informed about the products they browse. We’ve compiled a crash course on one of the most important aspects of gem value: weight.

Weight is written in carats for gemstones. To simplify things, we’ll explore diamond carat weight since it is one of the most popular stones for jewelry. This guide can be helpful if you’re searching for engagement rings, wedding rings, or simply your next statement piece.

Laying Some Quality Groundwork

Every gemstone, if sold from a reputable company, should come with a grade. You can either request a certification of your piece from a laboratory independently or request one from your retailer. Either way, this certificate helps to clarify the true worth of the stone based on noted categories.

When it comes to diamonds, this grading is done in a very specific manner. The Gemological Institute of America, founded in 1931, championed a method for diamond value. It gives out a grade based on four factors: diamond color, diamond clarity, diamond cut, and diamond carat weight.

Before we jump right into carat weight, let’s take a closer look at the other properties:


Colorless diamonds are considered to be the ideal. This traditional appearance allows for versatility in wear and excellent shine. Diamonds are also available in a wide range of hues for a special look.


Next in importance is how clear a diamond is. A perfect diamond option would be one that is virtually see-through. GIA clarity takes inclusions into consideration and grades based on how they disrupt the view of the inside of the stone. Clarity scores from this laboratory range from flawless (ideal) to included (poor clarity).


This grade may seem a little deceiving to those without background knowledge of gemstones. Gemologists grade the cut of a diamond based on how well it shows off its shine. This can be anywhere from Poor to Excellent, with Excellent being ideal.

What Is a Carat?

Let’s define what a carat is exactly. It is a unit of measurement for the weight of a gemstone. One carat is equivalent to 200 milligrams for an easy mental conversion. You can have a diamond with one-hundredth of a carat. (Note that “karat” measures gold purity.)

For example, a diamond that is slightly over half of a carat may be weighed at .56ct.

The milligram unit of weight is universally accepted, even in the United States, where we typically don’t use the metric system. System standardization keeps everything uniform among geologists and jewelers alike.

Historical Significance

When it comes to gemstones, most practices are rooted in age-old traditions. Rubies adorn the crowns of famous royalty, and emeralds go as far back as ancient Egypt.

Similarly, carat weight is based on the use of carob seeds to keep scales steady when weighing gemstones. Over hundreds of years, the seeds were replaced with a more professional means of determining gem weight.

Size vs. Carat

While a carat is a unit of weight, the size of the diamond (or gemstone) is another thing entirely. Size is based on more factors than simply weight and includes measurements of length and width as well. In general, the larger that a gemstone is and the more that it weighs, the more valuable it is.

This is true for most diamonds. However, it should be noted that diamonds rarely come in more than one carat. You can find jewelry that counts over one carat of diamond, but the stones are likely to be split into smaller pieces.

Finer Examples: Alexandrite

Another example of this is the precious exotic gem alexandrite. This traditionally June birthstone is one of our most prized offerings at Mark Henry Jewelry, but it is known to be available in smaller amounts.

Alexandrite is not commonly found in eye-clean, highly saturated quality above one carat. Brazilian alexandrite is some of the most prized, yet it weighs less than 0.25ct taken directly from the mine.

When you facet and cut a gemstone, the size goes down along with the weight. This is because certain gems favor different cuts to emphasize brilliance. During this process, carat weight can be cut significantly. In the case of alexandrite, a 0.25ct piece may diminish to 0.14ct after being cut.

Carat Charts

Diamonds are usually cut smaller than other gemstones. Despite this, diamonds are most commonly used throughout carat weight vs. size charts. These charts cannot be blanket statements for all gemstones. This is because the true weight of a gem comes down to its individual specific gravity, not size.

Specific gravity is a term used to describe a gem’s density.

Magic Size Markers

It can be alluring to hear the term “magic size” when jewelry shopping. It simply means that your gemstone is a carat, a three-quarter carat, or a half-carat. These weights are prized because they are even.

You might find yourself paying a bigger bill for one that is labeled as “magic.” Be aware that an uneven carat weight is just as valuable.

Consider the Bigger Picture

If you stumble upon a gorgeous ring with a gemstone that has a small carat weight, don’t count it out. Diamond value is not determined solely on carat weight. In fact, the total weight matters less than the other three C’s.

Acknowledge the unit of weight, but look at the other factors of the stone. For our case study, there may be larger diamonds with a poor cut or cloudy inclusions. They may be a different diamond with hints of unwanted color. When you consider everything, the diamond with fewer carats could be far more valuable.

Consult an Expert

If you’re struggling to compare stones in terms of value, there is no shame in asking an expert. It is always a good idea to reach out to someone who is qualified. Look for a gemologist who has a GG label. This means that they went through the GIA Graduate Gemologist program and are certified to help you.

Another way that you can get help is by reaching out to a GIA Applied Jewelry Professional. These retail associates might not examine your gem in a lab, but they can certainly tell you the basics. They have undergone training to do so, and they are amazing resources.

When shopping at Mark Henry Jewelry, our jewelers are on call to aid in a difficult buying decision. Read the description if you are stuck between two rings or bracelets but are unsure which one is more valuable. Looking solely at carat weight won’t tell you the whole story.

Reach out to our team through a chat on our website, or call a helpline. We can put you into contact with the best person to respond to your question. Don’t hesitate to inquire about gemstone certification, either. We are happy to assist in easing your worries by giving you a detailed breakdown of your stone’s quality factors.

Your Next Step

Mark Henry jewelry pieces are of the finest quality. From our headquarters in New York, we keep an eye on the sourcing of our gems from mine to hand. Our certification transparency speaks to our passion for the clearest pieces and cleanest choices.

Mark Henry’s Radiant Designs

Our Grande Signature Alexandrite Ring personifies everything we have discussed so far. With alexandrite mined directly from the finest family-run source in Brazil, this exquisite piece stuns wearers.

It features an 18kt gold band and halo effect baguette diamonds and round diamonds surrounding a stunning alexandrite. The baguette diamonds are 0.20ct, and round diamonds are 0.25ct.

With 0.98ct of alexandrite, all of the gemstones included are below one carat, shining as the finest examples of ethical, fine jewelry. Gems do not need to weigh an incredible amount to be luxurious and fantastic in design.

Another example comes from our Tic Tac Toe Ring. This piece is another alexandrite-diamond beauty, two gems that rarely exceed one carat. It is a more affordable ring than the former but comes with 1.30ct of alexandrite and 2ct of baguette diamond. Although just as gorgeous, this comparison proves that carat weight alone does not determine the price.

Find Your Carat Goals

At the end of the day, carat weight in a piece of jewelry comes down to your personal preference. Do you like heavier bracelets or lighter bracelets? How much weight can your finger take from an engagement ring that rarely comes off? Finding the perfect gemstone design and style for you can help you navigate a world of carat contentment.


Learn How to Buy a Diamond with the GIA Diamond Buying Guide | GIA

Standard Gem Sizes Chart | Gem Society

Learn What Carat Means and What Diamond Carat Measures | GIA

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