Delarah Banner

3-Carat Diamonds Buying Guide and FAQs

3 carat diamond guide

As Wedding Know How editors, we write about things that we love and we think you'll like too. We have affiliate partnerships and sponsorship and may generate some revenue from these at no cost to you.

A 3-carat diamond is sure to turn heads. These stones can cost exorbitant amounts of money and are exceedingly rare, making them a prestigious choice for any jewelry. However, purchasing a 3-carat diamond requires careful consideration as there are several factors to consider.

It’s important to note that carat refers to the diamond’s weight not size. 1 carat weight equals 0.200 grams which sounds light but is a very decent average weight for a diamond. With a weight of 0.600 grams, 3-carat diamonds are much rarer, more expensive, and quite highly valued.

Delarah Banner

If you’re considering buying a diamond and you’re wondering whether a 3-carat stone is worth it, below we’ve listed the most important factors you need to know about them.

1. How big are 3-carat diamonds?

1 carat diamond size
3 carat diamond size

Carat Size Preview on James Allen

Knowing a diamond’s weight is one thing but what most customers are interested in is how big a 3-carat stone actually is. Because the size of the diamond is largely dependent on the shape and cut of the stone, the carat measurement is used for diamonds – it’s simpler and more effective.

As the most popular cut for colorless diamonds is the round cut, a 3-carat round cut diamond will have parameters of 9.37 x 9.37 x 5.65 mm. In other words, it’d be almost a centimeter wide and over half a centimeter deep.

A 3-carat oval cut diamond, on the other hand, will have measurements of 11.7 x 7.8 x 4.76mm with some variations depending on the exact shape of the cut. These parameters will typically make the oval cut look bigger but the shallower build of the oval cut (by almost a full mm) tends to decrease its brilliance.

2. How much is a 3-carat diamond worth?

The price of a 3-carat diamond can vary as it depends on several factors such as the stone’s color, clarity, the quality of its cut, and many others. You can find 3-carat diamonds that cost as “little” as $19,000 and ones that go as far as $100,000 and beyond.

For example, G-color, VS1 clarity, ideal round cut 3-carat diamonds on James Allen range between $37,000 and $56,000 while D-color, IF/FL clarity, ideal round cut stones go up to $130,000.

3. How rare are 3-carat diamonds?

3-carat diamonds can be easily found at most larger jewelry vendors. The reason they are in shorter supply than 2-carat and 1-carat diamonds is simply that larger high-quality diamonds are harder to mine and refine – the larger the rough stone is, the more likely it is for it to have lots of inclusions and blemishes.

That’s why diamond cutters usually cut away most of the body of rough diamonds in order to maximize the brilliance and clarity of the final piece. It’s very common for a 5-carat or a larger rough stone to be reduced to 1-carat diamonds that look good. To cut a good looking 3-carat diamond, a cutter will usually have to work with an even larger rough stone. 

4. Is a 3-carat diamond a good investment?

Depends on what you’re looking for.

At face value, yes, a 3-carat diamond is a highly valuable jewelry piece. It looks great on most pieces of jewelry, it brings a lot of prestige with it, it makes for a great heirloom, and it has a very good resale value.

On the other hand, many would say that 3-carat diamonds are quite a bit of overkill. If you’re just looking for a diamond that would look great on an engagement ring and you’re not interested in the “prestige” it brings, going for a smaller diamond can save you a 5-digit sum of money while still looking great.

A 2-carat round cut diamond will have a width of ~8.2mm compared to the 3-carat diamond’s 9.37mm – this is about a millimeter of difference. It’s easy to see why a difference of just 1mm isn’t worth tens of thousands of dollars for many people.

A 1-carat round cut diamond will be ~6,5mm wide which is a more substantial difference compared to 9.37mm but still looks good on a ring.

So, if you just want a good-looking diamond for an engagement ring or another jewelry piece and you don’t want to spend your future kids’ college fund for it, going for 1-2-carat diamonds may be the wiser choice.

5. Do 3-carat diamonds look better?

Yes and no.

A high-quality 3-carat diamond will look stunning on most types of jewelry – there’s little doubt about that. With a size of around a centimeter, these stones are noticeable and awe-inspiring. A 3-carat diamond with high clarity and brilliance will always grab the attention of everyone in the room and will hijack most conversations.

On the other hand, the larger a diamond is, the more noticeable its imperfections are. Every diamond has at least some imperfections. So, while a single inclusion on a 1-carat diamond is easy to hide with a ring setting or is just harder to notice due to the stone’s smaller size, a single inclusion on a 3-carat diamond will usually be easily visible.

This is one of the many reasons why 3-carat diamonds are so rare and pricy – they have to be near-perfect to be worth buying.

6. Are 3-carat diamonds suitable for an engagement ring?

They can be if you’re adamant that such a large size will feel right for you. High-quality 3-carat diamonds do look impressive. If you want an engagement ring that will catch everyone’s attention, a 3-carat stone is guaranteed to do that. On the other hand, a 2.5-carat and a 2-carat diamond can do that as well for a fraction of the price.

Additionally, the larger size of the stone makes it much harder to protect it from wear and tear. They can get knocked or bumped easily which can compromise the integrity of the ring as well as the diamond.

A smaller diamond, on the other hand, will be much easier to keep safe from damage. This not only makes smaller diamonds more convenient for rings, but it also makes 3-carat diamonds even pricier over time as they’ll need more maintenance and repairs.

7. What metals and settings are right for 3-carat diamonds?

3-carat diamonds can be mounted on any type of metal and setting. Some people prefer white metals such as platinum and white gold for such large diamonds as this emphasizes the stone’s brilliance and colorlessness.

Also, since 3-carat diamonds are so large, they can reflect a lot of color and look less brilliant if set with yellow or rose gold. That being said, if you like the classic look of yellow gold, there’s nothing wrong with mounting a 3-carat diamond on it – the stone will still impress with its size alone.

As for the setting of the diamond, there are two ways of looking at this:

  • A more open setting such as a solitaire prong setting will keep as much of the stone exposed as possible which will maximize its brilliance. If you want your 3-carat diamond to look as stunning as possible and not be hidden by metal, such a setting can be a good choice.
  • A more closed setting such as a bezel setting will protect the diamond from damage such as knocks on hard surfaces. However, it does limit the stone’s sparkle and makes it appear smaller.

Which option you should go for will depend largely on what your lifestyle is, how often you want to wear the ring, and in what situations. For more active people, a closed and extra protective setting is usually advised. Then again, smaller diamonds are also recommended for such situations.

8. How do I buy a 3-carat diamond ring?

As mentioned above, most reputable jewelry retailers will stock 3-carat diamonds. However, not all 3-carat diamonds are created equal, so it’s essential that you do some research prior to purchasing. Here are our recommendations:

  • Shape – Choosing the shape of the diamond largely comes down to your preference. Each shape and cut has its pros and cons. In general, however, the round diamond is the most popular for diamonds of any size.
  • Cut – For large diamonds, cut is extremely important as it can make or break the diamond. Cut is always king, but in these cases, it’s even more important.
  • Color – It’s best to opt for a diamond that’s I grade or higher. If you drop below I, there’s a high chance the diamond will show very noticeable color. However, if you’re adding smaller accent diamonds to the ring setting, like a halo and pave, you can drop down on the color scale as long as the setting is made with accent diamonds with lower color. The contrast will make the center diamond appear much whiter than it is.  
  • Clarity – Look for a diamond with no visible inclusions, as flaws in the diamond are easy to see due to its large size. Opt for SI clarity grade or better.
  • Certification – Ensure that the diamond you purchase comes with a certificate of authenticity from a reputable lab, ideally the GIA which evaluates diamonds to stringent standards.

9. Where’s the best place to buy a 3-carat diamond?

Searching online will give you a wide range of choice and the chance of securing a stunning 3-carat diamond at a competitive price.

It’s essential that the purchase is made on a reputable site that has a proven track record of quality, customer service and competitive pricing.

We have been in the diamond and jewelry industry for many years and have consistently found that the following retailers are among the best:

  • Blue Nile – One of the first retailers who made the shift to selling diamonds online, Blue Nile is known for having the largest inventory of diamonds and settings online, stunning diamond quality, certification from quality labs and competitive prices. See their 3-carat diamonds here.
  • James Allen – James Allen has streamlined the process of purchasing diamonds and jewelry online, offering excellent customer service, high-quality diamonds and settings and a variety of services including no-pressure assistance from a diamond expert when purchasing. They also offer exceptional lab-created diamonds for a more affordable 3-carat diamond alternative. Search 3-carat earth mined and lab-created diamonds here.