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1-Carat Diamond: How Big Is A 1ct Diamond?

1-Carat Diamond: How Big Is A 1ct Diamond?

When purchasing a high-priced luxury item like a 1-carat diamond ring, you’d want to ensure you’re getting the best value for your money – and the most beautiful gem, of course. That is why, when buying diamonds, people usually ask: How big is a 1 carat diamond?

The approximate diameter of a 1-carat diamond is 6.5 millimeters. However, this isn’t the only factor you should consider when shopping for a diamond of this weight.

In this article, we’ve covered everything you need to know before opting for a 1-carat diamond for your ring. So, without further ado, let’s dive in.

Diamond Carat Size Doesn’t Exist

There’s no such thing as diamond carat size. People often confuse diamond carat for diamond size. However, you can easily avoid this mistake if you know some basics.

Diamond carat refers to the actual weight of the stone – it doesn’t affect the table surface area, diamond’s depth, or any other shape features. A higher carat weight doesn’t necessarily mean a bigger diamond, either.

On the other hand, a diamond’s size has to do with the actual visual appearance of the gem. 

For instance, a Marquise cut diamond will probably appear more prominent than a round brilliant cut diamond in the same carat category because of its elongated shape.

Several components, such as depth and surface area, play a role in the gem’s size. Thus, two diamonds of the same carat weight typically appear different in size based on cut quality and shape design.

How Much Is A 1 Carat Diamond Ring?

In general, a 1-carat diamond costs somewhere between $1700 and $12000. The price is based on several factors, though, including the quality of the cut, the shape of the stone, and the color and clarity grades.

Cut quality is the factor that dramatically affects a 1-carat diamond’s price – as well as its overall beauty.

Each 1-carat diamond price tag depends on more than one factor, which determines the beauty of the stone. But size is a significant driver of the diamond’s price – and even though carat isn’t explicitly a measurement of a diamond’s size, it’s correlated to it.

Carat is simply the measurement of the weight of the diamond. 1-carat equals 200 milligrams. So to put it in perspective, a 1-carat diamond weighs almost the same as a quarter of a raisin.

Remember that all diamonds are priced per carat. For instance, a 0.50-carat diamond may have a price of $1300 per carat – the price for this stone would be $1300 x 0.50, equaling $650.

See Also: How Much Is A 1 Carat Black Diamond Worth?

1-Carat Diamond Price Break Down

Diamond prices per carat go up as you reach higher carat weight categories. 

You see, diamond prices exponentially increase with carat weight due to the diamond’s higher weight value and the higher price per carat for the increased carat weight category.

For instance, a 1-carat diamond might be priced at $4600 per carat, while a similar 2-carat gem might be priced at $7300 – or more – per carat.

We stress the word “categories” because the prices per carat don’t continuously increase with the weight. After all, diamonds are retail products that are driven more by emotion and less by reason.

Even though it may seem advantageous to search for a stone that’s just below the next carat weight category – such as a 0.90-carat diamond – that isn’t the case.

The search for diamonds that are “almost” 1-carat diamond has become incredibly popular. However, people don’t realize that this popularity increases the price for those particular diamonds, which makes the cost savings minimal.

Diamond pricing is usually subjective because it’s all about feelings with diamonds. This aspect of “feelings” within the diamond industry is the biggest reason why there are plenty of poorly cut diamonds on today’s market.

Related Read: How Much Is a Rough 1-Carat (1ct) Diamond Worth?

1-Carat Diamond Shapes

A well-cut 1-carat diamond with a gorgeous ring setting will look stunning in any diamond shape. As such, you should primarily select the diamond shape based on personal preference.

For those concerned with the size of the diamond, there is a difference in the surface area among 1-carat diamond shapes. Depending on their differing table sizes, the 1-carat might appear larger.

The chart below will give you an insight into surface area differences among different diamond shapes.

Diamond Shape Table Surface For 1 Carat
Round Brilliant Cut6.5*6.5 millimeters
Asscher Cut5.61*5.61 millimeters
Emerald-Cut6.68*4.95 millimeters
Oval-Shaped Diamond8.12*5.41 millimeters
Pear-Shaped Diamond9.05*5.45 millimeters
Radiant Cut5.78*5.78 millimeters
Heart-Shaped Diamond6.56*6.56 millimeters
Marquise Diamond10.38*5.19 millimeters
Cushion Diamond5.83*5.83 millimeters

Tips For Buying A 1 Carat Diamond Ring

If you want the best-looking 1-carat diamond ring, this section is for you. Read on!

Find The Right Style For Your Ring

Before finding your diamond for the centerpiece of your ring, it’s probably best to have a rough idea of what you want it to look like in the first place. That way, you can save a portion of your budget for the ring itself and increase it for the diamond.

For a 1-carat diamond ring, virtually any style will look amazing. However, some styles stand out from the rest, such as:

Take into consideration the precious metal your ring is going to be made out of, too. 

Different gold colors have a negligible impact on the price. However, if you need platinum for your ring setting due to a metal allergy, this can increase the cost of the ring.

Learn More: Types Of Diamond Settings: A Guide To Setting Styles

Consider Different Diamond Shapes

If your heart’s not set on a round brilliant cut, be sure to check out other diamond shapes

At the 1-carat mark, average prices of fancy-shaped diamonds are up to 42% less compared to a round brilliant – that’s a lot of savings.

Princess cut gems are among the most popular fancy-shaped diamonds, while cushion cut diamonds are an old favorite. Oh, and the trendy pear and oval diamond shapes will make the finger appear thinner and longer. 

Choose wisely!

Limit Your Options To The Best Cut Diamonds

There are hundreds of thousands of diamonds on today’s market. The right one for you is bound to be out there. However, you’ll need to limit your options. 

While you’re at it, limit yourself only to well-cut stones.

Although there are 4C’s for diamond grading, the cut is the most crucial aspect of the diamond’s beauty. A fantastic cut will hide color in a lower-grade stone and inclusions within a gem with a lower clarity grade. Better yet, the intense sparkle of a particularly well-cut gem will make the stone appear more prominent.

So, if you hope to save money, you can do so by compromising on clarity and color.

For round brilliant cut diamonds, if you want to find the one with the best cut, limit your options to “excellent” cut grade by GIA or “ideal” cut grade by AGS. Then limit the table percentage to 54-57% – and depth percentage to 58-63%. 

Read Also: Which Diamond Cut Sparkles The Most?

Finding The Best Color Grade

Diamond’s color grade can also have an impact on price – although not as big as the cut. To get the most for your budget, we recommend going for the lowest color grade that will still look white in the ring setting you’ve selected.

For three-stone rings and halo rings, be sure to stick to the same color grade as all diamonds in the ring. If you go for a lower color grade for your center stone, it might appear off-color in the setting.

For these styles, we recommend sticking to the H color grade. However, if you need to stretch your budget, even I and J color grades could work.

For solitaire ring settings – including those with the channel or pave set diamonds in the band – the best color depends primarily on the precious metal of the ring. 

If you choose a ring setting online, be sure to check the color of the prongs. Some ring settings mix precious metals. For example, they might put white gold prongs on a yellow gold ring.

For white gold and platinum prongs, diamonds with I and J color grades will still look white while giving you a nice discount.

Yellow gold is a bit more forgiving and makes the stone appear whiter. K and L color grades will work well in a yellow gold ring setting.

Rose gold is excellent in hiding the stone’s color, making diamonds with L and M color grades a great choice.

Consider Lower Clarity Grades

For a 1-carat diamond, you virtually don’t need a flawless stone. 

As a matter of fact, we recommend against stones with the highest clarity grades because they increase the cost without adding much to the overall value.

If you still have plenty of choices after narrowing down the color and cut, we advise going for a diamond with a VS2 clarity grade. These stones will be “eye-clean” at a reasonable price.

If a VS2 clarity grade stone is out of your budget, don’t worry: 

At 1-carat, most diamonds with an SI1 clarity grade are eye-clean. That is also true for many SI2 and even I1 graded diamonds. 

We recommend avoiding black inclusions close to the diamond’s center as these are generally the most noticeable.

For stones with lower clarity grades, it’s helpful to zoom out from the high magnification – you won’t see the dark spots anymore. 

If you’re looking at stones in the clarity range from SI1 to I1, we recommend consulting with a diamond expert.

Related Read: Are I1 Diamonds Good For Earrings? What Are I1 Diamonds?

Narrowing Or Expanding Choices

When searching for the best diamond for you, you may find yourself with plenty of choices – or very few.

If you do find yourself with a ton of choices, chances are you have a large budget. Rather than going for higher clarity or color grade, why not opt for a higher carat?

You can gradually increase the carat weight in your searches until you have, let’s say, 25 to 35 diamonds to choose from – and go from there.

With a smaller budget, it gets a bit more complicated. You might want to loosen your clarity or color grade criteria in order to get more options.

If your budget for the diamond is under $3000, you’ll likely have a hard time finding a well-cut 1-carat diamond.

If loosening your clarity and color grades criteria still don’t leave you with acceptable options, you could go for a 0.90-carat diamond – or even choose a sub-par cut. 

Even with the loss of carat weight, a well-cut 0.90-carat diamond may actually appear bigger than a poorly cut 1-carat stone.

Find The Sparkliest 1-Carat Diamond

If you want a gorgeous-looking gemstone, you’ll want to find the one with the most sparkle. That dramatically increases the overall beauty of the stone. 

So, find a diamond that offers a good amount of fire and brilliance.

The sparkle you see in the diamond’s crown might be a bit distracting – but try to look straight into the center of the stone and ensure this area also has a significant amount of sparkle. 

Also, be sure to compare several different stones before determining your top choice, and don’t forget to ask a professional for advice.

Other Factors

When shopping for a 1-carat diamond ring, you might be tempted to limit your choices to stones with excellent polish and symmetry. It sounds better, right? 

But in reality, though, you won’t be able to differentiate stones with Good and Excellent polish grades.

Similarly, you might have heard about fluorescence in diamonds and how bad it is. However, as long as you avoid diamonds with a Very Strong fluorescence grade, you won’t be able to notice any difference.

Finally, the word on the street is the Hearts and Arrows diamond cut is the best choice. That makes very little difference to the diamond’s performance – as it’s more related to the diamond’s symmetry than to the quality of the cut.

Unless you prefer Hearts and Arrows, you can save money by selecting a different diamond cut.

Related Read: What Is The Cheapest Cut Of Diamond?


So, how big is a 1 carat diamond? 

A 1-carat diamond is 6.5 millimeters in diameter – but keep in mind that we’re talking about the size of a round brilliant cut diamond with ideal proportions. Other shapes may have smaller – or bigger – surface areas.

Shapes like oval, marquise, and pear have a more extensive surface area, while Asscher and princes cut diamonds are smaller, with around 5.5 millimeters table size.

While they seem small, a 1-carat diamond is big enough to draw attention. While carat weight and size should be considered, you should also focus on selecting a well-cut stone. 

On top of that, you should take note of the clarity and color grades when choosing a 1-carat diamond for your ring.

That’s about it. We hope you make the right choice!

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