Is Carat a Weight or a Size?

Is Carat a Weight or a Size?

Posted by Koorosh Daneshgar on Mar 15th 2021

Diamond Size vs. Carat Weight

Is Carat a Weight or a Size?

Is Carat a weight or a size? Carat is a unit for measuring the weight of diamonds. The carat weight is also a means of determining a diamond’s price value, since diamonds of high carats are more expensive. On the other hand, the size of a diamond refers to the measurement of its height and width, for which we use millimeters as the unit. Size is not a determinant of the price.

One of the women’s priorities is to choose a bigger diamond, for which they usually consider more carat weights. However, you need to make sure that you do not sacrifice the sparkle of your diamond by making wrong decisions of the weight and size due to lack of enough diamond education or misinformation.

What is the carat weight?

Carat is a unit for weighing diamonds. Carat weight is also one of the most significant factors in determining the diamond price. Although other factors, such as clarity, color, and cut, are determinants of a diamond’s value, the price of the diamond is mostly under the influence of its carat weight.

The etymology of the word carat goes back to “carob seed” according to Wikipedia. Gemologists, appraisers, jewelers, and clients conventionally use the term carat in their discourse for referring to the weight of a diamond. The reason for using carat instead of other units is for being incredibly smaller than the rest. One carat is equal to 200 milligrams, or 0.02 grams, which are not always easy to remember.

For evaluating the weight of the most valuable and expensive stone on Earth, we need to minimize our unit as much as possible. Therefore, an even smaller unit compared to carats is called points; 1 carat is equal with 100 points. The carat weight functions as an important factor in determining the price. For that reason, in case all the other Cs (cut, clarity, carat, and color) are equal, a diamond with a lightly more carat weight is much more expensive than the other is.

What does carat size mean?

The term does not exist in the discourse of diamond jewelry. Since carat is the measurement unit for diamond weight, it has nothing to do with diamond size. In other words, clients use the term ‘carat size’ mistakenly for referring to the dimensions of a diamond’s surface area on the top. We use millimeters for talking about the size of a diamond.

Unlike the weight of a diamond, which the naked eye cannot see, the size of a diamond is understandable. In other words, the mass gathering at the surface area on its upper part, which we call the crown, is what the naked eye decides as the largeness of a diamond.

The size of a diamond is the measurement of its width and height. We refer to the former as the diamond’s diameter and the latter as its depth. Unlike the depth that adds to the weight, the diameter displays the largeness of the diamond from the top view.

What is the smallest diamond size?

The smallest diamond that designers recommend you to choose for a diamond ring is one-quarter of a carat. The size of a round brilliant cut diamond of 0.25 carat is 4 millimeters. Diamonds with very much less than the size and weight mentioned looks similar to Melee diamonds.

We recommend you to set a 25-point diamond, equivalent with 0.25 carat, on your engagement ring if you are a fan of smallish and elegant stuff. For slim fingers, one-quarter of a carat diamond set on a thin metal band matches the required delicacy. Depending on the diamond shapes, one-quarter of a carat may have different sizes:

  • Round brilliant: 4 millimeters
  • Princess cut: 3.25 millimeters
  • Cushion cut: 3.5 millimeters
  • Oval: 5x3 millimeters
  • Emerald cut: 5x3.3 millimeters
  • Heart: 4 millimeters
  • Pear: 5x3 millimeters
  • Marquise: 6x3 millimeters
  • Asscher cut: 3.4 millimeters
  • Radiant: 4.3x3.2 millimeters

In the jewelry business, designers use melee diamonds for creating a halo around the center stone or to pavé the setting. Melee diamonds are extremely small and usually have the shape of a round brilliant, yet they only possess 17 and 18 facets due to their pettiness.

What is a good diamond size?

What is a good diamond size?

The best diamond size depends on its cut quality and carat weight. Since the carat weight of a diamond is highly dependent on your budget, you need to invest in the cut quality of your diamond. A perfect diamond size covers enough of your finger and provides an ideal cut quality. A 1-carat diamond has the most popular size in the U.S., which is 6.5 millimeters.

As discussed above, the size of a diamond is the millimeters of its diameter and depth. What we see as the size of a diamond is its surface area from the top view, which is the table and crown of the diamond. A big-sized diamond from the top has a larger diameter, table, and crown.

If you choose a diamond with a large surface area, you will sacrifice its cut if it lacks enough depth. A shallow cut diamond cannot afford the desired sparkle and fire you wish. To educate yourself with the importance and functionality of cut quality read this blog post.

Therefore, make sure that the different parts of your diamond possess enough millimeters. If by the best diamond size you mean the most popular, the average in the U.S. is 6.5 millimeters, which belongs to 1-carat round brilliant diamonds. For the inhabitants of Chicago, the most well-wanted carat weight is 1.29, which is almost 7 millimeters in a round brilliant cut.

Why carat weight is not the same as size?

Weight and size are different, for they have different functionalities. Apart from their responsibilities, they also have different units of measurement. Carat is simply the weight of a diamond, which determines its price. On the other hand, size is the measurement of different proportions in millimeters.

Although weight and size greatly influence, correlate, and are affected by each other, they have different functionalities. To say that, each represents different characteristics of a diamond, and different parameters determine each. While unnoticeable from the top view, the depth of a diamond determines its number of carat weights. On the other hand, more millimeters of diameter make a bigger diamond size from the top. For example, two diamonds of equal weights may have different dimensions.

However, what matters the most is that different parts of the diamond have to be proportional. Whereas long diameter makes a bigger size for a crown, high depth causes more carat weight. The former is too deep, and the latter is too shallow, which means that neither creates an ideally beautiful and sparkly diamond, for they lack proportionality. Therefore, when you go shopping for diamonds, make sure their different parts are proportional and do not sacrifice the cut quality.

What is most important when buying a diamond?

Cut quality is the most important attribute of a diamond, for it determines the quality of reflection and scintillation. Unlike other Cs, cut quality does not exclusively depend on the rarity of the diamond since experts cut diamonds in laboratories. Therefore, you need to purchase a diamond with ideal proportions.

This video explains all the Cs, including the most important one:

Is more carats better for diamonds?

More carats does not indicate the favorability of a diamond, but it does the price. Since carat is a unit for evaluating weight, it does not determine the overall beauty of the diamond. However, more carats for a diamond means it is rarer and more expensive. In other words, the price of a diamond increases with its carat weight drastically.

How do you tell how many carats a diamond is?

Although carat is the most popular unit for measuring the weight of diamonds, there are other terms as well. The written and spoken form of the units, from the biggest to the smallest, are:

0.02 g = two-hundredth grams

200 mg = two-hundred milligrams

1 ct. = one carat

100 pts = one-hundred points


Why should I come to you to design my ring?

We involve you in every step of the process. At first, we will sit next to you and go over any concerns you have and any specific design elements you mind the ring to have. Once we have established exactly how you want the ring looks like, we will proceed with the design process. Once you see this design, if you want to make any change or if you have any questions or concerns we will be happy to address them for you. Our role is to help you to create the perfect ring and that means we will listen to you and make sure that your ring is indeed one of a kind.

The best designer and jeweler in Chicago Jeweler’s Row

By: Koorosh Daneshgar CEO/Design Chief