(917) 720-6618

20% Off All Jewelry!

FREE SHIPPING  |  30 DAY RETURNS

Browse

Want to chat?

917 764 9222

Diamond Carat

Discover the details of carats: the unit of measurement used to describe diamond weight.
Shop Diamonds

What is a Carat?

A carat is a unit of weight used specifically to measure diamonds and other gemstones. It is often mistaken for a measurement of size, but a carat is actually a measure of how much a gemstone weighs. One carat equals 0.2 grams, roughly the weight of a small paperclip.

The term “carat” originated from the use of carob seeds as a standard for weighing gemstones due to their uniform weight.

The Evolution of the Carat System

The concept of the carat has ancient roots. Gem traders historically used carob seeds as a counterbalance on scales because of their consistent weight. However, there was no global standard for gemstone measurement until 1913, when the metric carat was internationally adopted. Today, a carat is a standardized measurement used worldwide, ensuring consistency across the gem industry.

Carat vs. Karat

It’s important not to confuse “carat” with “karat,” which is a measure of gold purity. While both terms are used in the jewelry industry, they refer to entirely different properties—weight for carats and purity for karats.

Carat and Size: The Difference

Although a carat measures weight, it is often wrongly assumed to indicate the size of a gemstone. The actual size of a gemstone is influenced by its density, shape, and cut. For example, a one-carat diamond might appear larger or smaller than a one-carat sapphire due to differences in density. Additionally, a gemstone’s shape and cut can significantly affect its perceived size. A round diamond, for instance, might have a diameter of 6.4mm at one carat, whereas a similarly weighted round sapphire could measure 6.0mm.

How Carat Weight is Measured

Carat weight is measured using precise instruments such as micro-balance scales, which allow gemologists to divide a carat into 100 ‘points.’ This precision ensures that the carat weight is accurate to the thousandth of a decimal place, providing a reliable basis for assessing a gemstone’s value.

Actual Diamond Size on Size 6 Hand

0.1 CT
0.25 CT
2.00 CT

Carat and Price: The Relationship

Carat weight is one of the four critical factors—alongside cut, color, and clarity—used to determine a diamond’s quality and value. As carat weight increases, so does the rarity and, consequently, the price of the gemstone. This relationship, however, is not linear. Larger diamonds are rarer and therefore command a much higher price per carat. For instance, a one-carat diamond is often significantly more expensive than two half-carat diamonds of the same quality.

Certain carat weights, known as “magic sizes” (such as ½ carat, ¾ carat, and 1 carat), are particularly sought after. Diamonds that cross these thresholds are priced at a premium, even if the difference in size is barely noticeable.

Factors Affecting the Perceived Size of a Diamond

Carat weight isn’t the only factor that influences how large a diamond appears. The shape, depth, and symmetry of a diamond also play critical roles. For example, elongated shapes like oval or emerald cuts can make a diamond appear larger because they distribute weight over a larger surface area. Conversely, diamonds with greater depth might look smaller despite having the same carat weight.

Enhancing the Appearance of Size

Several strategies can make a diamond appear larger without increasing the carat weight:
  • Halo Settings: Surrounding a central diamond with smaller stones can create the illusion of a larger centerpiece.
  • Delicate Bands: A thinner band can make the central stone seem more prominent.
  • Regular Cleaning: Keeping a diamond clean ensures it sparkles and appears as large and brilliant as possible.

Diamond Carat FAQs

The average carat weight for engagement rings typically falls around 1.0 to 1.5 carats. However, this can vary based on personal preferences, budget, and regional trends.
Lab-grown diamonds have the same carat weight as natural diamonds, as carat measures weight, not origin. The average carat weight for lab-grown diamond engagement rings is similar to natural diamonds, often ranging from 1.0 to 1.5 carats, but they are generally more affordable, allowing for a larger stone within the same budget.
A 1-carat diamond’s size can vary depending on its cut, shape, and depth. For example, a well-cut 1-carat round diamond typically measures around 6.4mm in diameter, but this can look different based on the diamond’s setting and shape.
The price of a diamond increases significantly with carat weight, but not linearly. A 2-carat diamond can cost much more than double the price of a 1-carat diamond of similar quality because larger diamonds are rarer and more sought after.
Yes, factors such as the diamond’s cut, shape, and depth can all influence how large or small a diamond appears. For instance, elongated shapes like oval or emerald cuts can make a diamond appear larger than a round diamond of the same carat weight.
While carat weight is important, it’s essential to balance it with other factors like cut, clarity, and color. A well-cut diamond with good clarity and color can appear more brilliant and attractive than a larger diamond with poor quality in these areas.
CTTW stands for Carat Total Weight and refers to the combined carat weight of all diamonds in a piece of jewelry. This is different from the carat weight of a single stone. For example, a pair of diamond earrings might have a CTTW of 1.5 carats, meaning the total weight of both diamonds combined is 1.5 carats.
Yes, certain settings, such as halo settings, or choosing a shape with a larger surface area, can make a smaller carat diamond appear larger. Additionally, a thin band can emphasize the size of the center stone, making it look more prominent.
“Magic sizes” refer to specific carat weights, such as 0.50, 0.75, and 1.00 carats, where there is a significant jump in price. These sizes are popular benchmarks, and diamonds just above these thresholds tend to be much more expensive than those just below, even if the visual difference is minimal.