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Actual Diamond Size on Size 6 Hand
What Is Diamond Carat?
Diamond carat is the standard unit of measurement for a diamond’s weight. One carat equals 0.2 grams—roughly the weight of a paperclip.
Carat weight is one of the four primary factors that determine a diamond’s quality. It is often misunderstood: many assume carat refers to a diamond’s size rather than its weight, and it is sometimes confused with karat, which measures the purity of gold.
The diamond carat measurement system originated with early gem traders, who used uniform carob seeds as counterweights to balance their scales. Until 1913, carat weight varied across regions, but the adoption of the modern metric carat created a universal standard still used today.
Carat weight is important when selecting a diamond, as it directly influences both appearance and price. By understanding carat weight, you can confidently compare diamonds and decide how to balance visual impact and budget.
How Is Diamond Carat Measured?
To ensure consistency, precision, and accuracy, diamond carat is measured by professionals with specialized micro-balance scales. Within this system, one carat equals 200 milligrams, and each carat is divided into 100 'points' to allow exact measurements to the thousandth decimal place.
How Big is a Carat?
A carat is synonymous with weight, not with the size of a diamond or other gemstone. For example, because of varying densities, a one-carat round diamond may measure 6.4mm, while a one-carat round sapphire might measure 6.0mm. Shape, cut, and depth also play a role in determining how big a carat appears.
This diagram illustrates the typical size relationship of round diamonds in increasing carat weights. Remember, every gemstone is unique, and the appearance of carat weight varies.
Carat Weight vs. Carat Size: Is Carat the Size of the Diamond?
No, carat is not the size of the diamond. Carat is a metric unit that measures weight — not size. Equating the two may seem logical, but diamond carat and diamond size are not the same thing. It’s best not to use carat weight alone to estimate a diamond’s size.
For example, different gemstones have different densities (mass per unit of volume), meaning that two gems with the same carat weight may exhibit very different sizes.
The cut of a gemstone can also affect its carat weight. If a round diamond is poorly cut, it may be too deep or have an extra thick girdle. If excess weight is hidden around the girdle, it won’t display once set, which means that a 1.20-carat diamond with a ‘hidden’ weight may look the same size as a 1-carat diamond. So, a customer might pay for the added weight with no visual benefit.
Diamond Carat Size Chart
The following chart estimates the average size of differing diamond shapes in various carat weights. Each image shows what it looks like when viewing the diamond from the top down. As you’ll notice, two diamonds may appear to be different sizes with the same carat weight — this is because shape (in addition to density and depth) plays a big role in how carat weight is visually represented.
Actual Diamond Carat Size on Hand
Diamond Carat Price
Carat weight has a significant impact on price. Larger diamonds are much more valuable because they are discovered in nature less frequently than small diamonds. This means that diamonds are not priced linearly — a one-carat diamond will cost more than two half-carat diamonds of the same quality.
Carat’s impact on price is clearly displayed when considering what the diamond industry refers to as ‘magic sizes.’ At certain weight boundaries (a ½ carat, ¾ carat, and 1 carat), or ‘magic sizes,’ the price per carat increases dramatically. These set boundaries coincide with popular weights, which means greater demand and even greater prices.
For example, if one diamond weighs 0.97 carats and another of the same cut, color, and clarity weighs 1.03 carats, you probably wouldn’t be able to tell the difference between the two. However, the cost difference will be significant because the second diamond is over the ‘magic’ threshold of one carat.
Is Carat the Only Factor That Affects the Size Appearance of a Diamond?
No, carat weight is not the only factor that affects the size appearance of a diamond. A diamond’s shape, depth, and symmetry also affect how big (or small) a diamond looks.
Elongated shapes (such as oval and emerald) appear larger than 1:1 diamonds (such as round) because elongated shapes can carry most of their weight in their length as well as their depth.
Two diamonds of the same shape with different depths will also have different size appearances. For example, a one-carat pear with a shallow depth will look much larger than a one-carat pear with a deep depth.
Both depth and shape are factors listed on a diamond’s official certification report. Reference them to maximize size without the added cost of extra carat weight.
How to Make a Diamond Look Bigger
- Enhance with a Halo Setting: Choose a halo setting that features smaller diamonds that surround the center stone in shimmering light to increase the size appearance of your center stone.
- Select a Delicate Band: The smaller the band of your setting, the larger your stone will appear. If the band of your setting is thick, it will draw attention away from your center stone and make it seem relatively small compared to the band.
- Utilize an Elongated Shape: Elongated diamond shapes that maximize surface area, such as marquise, oval, and pear, tend to look larger than other shapes of the same carat weight. These shapes elongate the diamond, creating the illusion of a bigger size. Choosing a shape with a larger table facet can also enhance the diamond's apparent size.
- Highlight with Bright Metals: Platinum and white gold can blend in seamlessly with a colorless diamond. Without the boundaries of the diamond being emphasized, these white metals can make the diamond center stone appear larger.
- Consider a Lab Grown Diamond: With lab diamonds, you can purchase a much higher carat weight for a lower price than a smaller natural diamond. Optically, chemically, and physically the same as their natural counterparts, lab diamonds are an excellent option for anyone looking to make a big statement with their center piece at a more accessible cost.
- Maintain Brilliance with Regular Cleaning: Ensure that your diamond sparkles brightly by following tips on proper cleaning and care. A dull, dirty ring may look less impressive and smaller than a shimmering, clean ring.
Diamond Carat FAQ
What's the average carat size for engagement rings?
The average carat for engagement rings is around 1.5 carats. The average lab diamond engagement ring is typically slightly larger than its natural counterparts.
How much is a 1-carat diamond ring?
The average cost of a 1-carat natural diamond ring is $7,500. The average cost of a 1-carat lab diamond ring is $3,500.
How much is a 1.5-carat diamond ring?
The average cost of a 1.5-carat natural diamond ring is $13,000. The average cost of a 1.5-carat lab diamond ring is $5,500.
How much is a 2-carat diamond ring?
The average cost of a 2-carat natural diamond ring is $20,500. The average cost of a 2-carat lab diamond ring is $7,500.
How much is a 3-carat diamond ring?
The average cost of a 3-carat natural diamond ring is $36,500. The average cost of a 3-carat lab diamond ring is $13,000.
How much is a 4-carat diamond ring?
The average cost of a 4-carat natural diamond ring is $48,000. The average cost of a 4-carat lab diamond ring is $19,000.
Carat vs. karat: what is the difference?
Carat and karat sound alike; however, they measure completely different things. One measures weight and one measures gold purity. Let’s break down what each term means and why they matter when you’re buying jewelry:
- Carat: A carat (ct) is the standard unit for measuring gemstone weight, with one carat equal to 200 milligrams (0.2 grams). In modern jewelry, carats provide an exact measurement of a stone’s mass, though this doesn’t directly translate to its visible size or dimensions. For instance, a 1-carat round diamond may appear different in size from a 1-carat oval diamond, even though they weigh exactly the same.
- Karat: Karat (K) measures the purity of gold in an alloy, expressed as parts per 24. Pure gold is designated as 24K, meaning all 24 parts are gold with no other metals present. For example, 18K gold contains 18 parts pure gold and 6 parts other metals, making it 75% pure gold. This system allows jewelers and consumers to understand the exact composition of gold jewelry and helps determine its value and durability.
The primary distinction between these terms lies in their measurement purposes. Carats measure physical weight using precise decimals (such as 1.75 ct), while karats measure gold purity typically in whole numbers (10K, 14K, 18K, 24K).
What does carat mean in diamonds?
In diamonds, carat is the standard unit of measurement for a diamond’s weight. One carat equals 0.2 grams—about the weight of a paperclip.
Which diamond shape looks biggest for carat size?
Diamond shapes that maximize surface area look the biggest for carat size. Marquise, oval, pear, and other elongated diamond shapes tend to look larger than other shapes of the same carat weight. These shapes lengthen the diamond, creating the illusion of a bigger size. Choosing a shape with a larger table facet can also enhance the diamond's apparent size.
