Jewelry Guide

3-Carat Diamond Engagement Ring – Comprehensive Buying Guide

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If you’re leaning towards a large, eye-catching diamond, a 3-carat stone is ideal. It’s much above average in size and will surely turn heads.

3-carat diamond engagement rings are quite a considerable purchase, so it’s important to be well-prepared when approaching it. The diamond jewelry niche is a world of many complicated numbers, terms, and concepts that can be disheartening when you’re about to make a 5- or even 6-digit purchase.

With that said, what do you need to know before you buy a 3-carat diamond engagement ring? Let’s start with the 4Cs of diamonds – carat size, cut, clarity, and color.

How Big Is A 3-Carat Diamond Exactly?

3 carat diamond weight

The carat size of a diamond actually measures its weight and not its dimensions. 1 carat of weight is equal to 600 milligrams or 0.6 grams, so a 3-carat diamond will weigh exactly 1.8 grams – about the same weight as a raisin.

But how big is that exactly in terms of the stone’s proportions?

This will depend on the cut and shape of the stone, which we’ll cover next. But the rough proportions you can expect from the stone are around 8x8x6 millimeters.

James Allen 3 carat diamond tool

James Allen Carat Size Preview Tool

Whether that’s too big for an engagement ring or not is a matter of personal preferences. To see how this will look on the average hand, some retailers such as Blue Nile and James Allen offers a useful tool which allows you to choose the size of the diamond and see how it looks on the finger. This gives you a good representation of the size of a 3-carat diamond in comparison to other popular diamond sizes.

What Cut Should You Go For?

3 carat diamond and cut

Outside of the carat size, a diamond’s cut is its most important feature. It’s easy to conflate a cut with shape but the two are actually different. Cut encompasses the diamond’s shape but also refers to technicalities – symmetry of the cut, whether there are any noticeable defects after the cutting process, and so on.

As a result, the cut of the diamond matters in several different ways:

  • The better the cut, the better the diamond will look. This is especially important for large diamonds such as 3-carat ones, as every small imperfection can be easily seen in such a large stone. While for a 1-carat diamond you can easily ignore some minor defects, on a 3-carat stone everything is easily noticeable. These defects don’t just include issues created during the cutting process – they also include the natural internal flaws of the diamond that reduce its clarity. One of the main goals of a diamond’s cut is to hide such flaws.


  • The shape of a diamond is a component of its cut. It also affects the overall look of the stone. Especially for stones that are as big as 3 carats, different shapes can have significant effects in two ways:
    – Different shapes have varying physical dimensions
    – Different shapes have varying light performance and brilliance
    As far as the stone’s brilliance is concerned, the Round Brilliant cut, the Oval cut, the Princess cut, and the Radiant cut produce the most brilliance, typically in that order. These are the approximate dimensions of 3-carat diamonds depending on their shape:
Diamond shape Approximate table surface area
Round Brilliant Cut 9.37×9.37×5.65mm
Princess Cut 7.95×7.95×5.72mm
Emerald Cut 9.64×7.14×4.64mm
Asscher Cut 8.1×8.1×5.27mm
Radiant Cut 8.33×8.33×5.33mm
Cushion Cut 8.4×8.4×5.38mm
Oval Diamond 11.7×7.8×4.76mm
Pear Shaped Diamond 13.05×7.86×4.79mm
Heart Shaped Diamond 9.46×9.46×5.68mm
Marquise Diamond 14.98×7.49×4.57mm
Trillion Diamond 11.16×11.16×4.46mm


  • The cut of the stone also affects its price. This should go without saying but the higher the cut grade, the more expensive the stone is going to be. Most experts state that ‘cut is king’ and shouldn’t be compromised. If your budget allows, go for higher cut grades, as these are more brilliant and stunning in appearance.

What Clarity Grade Should Your 3-Carat Diamond Have?

After the diamond carat weight and cut, its clarity is the third most important factor. The clarity of a diamond refers to how clear the stone is – how devoid of any internal or external inclusions, blemishes, or other flaws. Most of these are typically natural and they become a part of the stone during its formation in the Earth’s core. Some can be due to poor craftsmanship during the cutting process.

GIA diamond clarity chart

The value of a diamond with good clarity should be obvious – the clearer the stone is, the higher its brilliance and the better its look. Different gemology institutes have different clarity grades but most of the major institutions use the following grading system or a variation of it:

  • IF (Internally Flawless) and FL (Flawless) diamonds. These stones no internal inclusions that are visible under x10 magnification. 3-carat IF or FL stones look spectacular but are a bit pricey too.
  • VVS1 & VVS2 (Very Very Slightly Included) diamonds. These diamonds have some minor inclusions but they are invisible to the naked eye and can only be seen under x10 magnification. A VVS1 or VVS2 3-carat stone can look as good as an IF or FL one.
  • VS1 & VS2 (Very Slightly Included) diamonds. These stones are almost completely clear to the naked eye. Their inclusions are significantly easier to notice with a magnification tool. This tends to be the best budget-friendly option for 3-carat diamonds as it’s the most affordable clarity that’s still eye-clean.
  • SI1 & SI2 (Slightly Included) diamonds. The inclusions on these two grades are much easier to see with the naked eye. Occasionally, you can find an SI1 or SI2 stone where the inclusions are nicely placed and fit the stone’s color so that they are not easy to see. On a 3-carat stone, however, they’ll almost always be visible.
  • I1, I2, and I3 (Included) diamonds. These diamonds have many large inclusions that are easy to notice. They are completely unsuitable for a 3-carat diamond.

Generally, VS1 and VS2 diamonds and above are recommended for 3-carat diamond engagement rings. Always make sure you see the actual diamond rather than a stock image, when purchasing. Some retailers have HD, 360 degree videos and zoomed in images which allow you to see every aspect of the stone from every angle. In our view, this is even better than seeing the diamond in person, as you get to take your time and view every flaw of the stone with the help of state-of-the-art imaging. James Allen even offers a Real-Time Diamond Inspection option which lets you see the actual stone in real time.

What’s the Right Color Grade for A 3-Carat Diamond Engagement Ring?

Diamond color chart from perfect colorless to noticeable color

The Color (or lack thereof) of colorless diamonds is measured on an alphabetical scale from D to Z. The A, B, and C grades are skipped because in the early days of diamond color grading, gemologists and merchants were abusing these grades too much (A, A+ AAA, AAAAA, etc).

So, today, the diamond color grades most gemological institutes use look like this:

  1. Colorless: The D, E, and F grades – the rarest, best-looking, and most expensive color grades.
  2. Near Colorless: The G, H, I, and J grades – great looking and best value color grades.
  3. Faint Color: The K, L, and M grades – good-looking color grades that can look well with the right setting or ring metal but may not be suitable for a large diamond.
  4. Very Light Color: N to R grades – the color hues on these stones tend to be too unappealing, especially for larger stones and they are rarely used as centerpiece stones in jewelry.
  5. Light Color: S to Z grades – these color grades are almost never used in jewelry, especially on large stones such as 3-carat diamonds.

Anything that’d go after Z would be considered a “Fancy Colored Diamond” and isn’t a colorless diamond. Fancy colored diamonds are actually even rarer than D, E, and F colorless diamonds and are even more expensive.

JamesAllen Engagement Rings

Of the colorless diamonds’ spectrum, the G-I range is typically recommended for engagement ring diamonds of any size, including 3-carat stones. That’s because their slight color hues are almost unnoticeable to the naked eye even on large stones and they are more affordable than D-F color diamonds.

However, if budget allows, you can go higher up on the grading scale for the most colorless diamonds.

What’s the Right Ring Setting For A 3-Carat Diamond?

There are many different settings for engagement rings you can choose from:

  • Prong setting and solitaire setting
  • Bezel setting
  • Tension setting
  • Pave setting
  • Channel setting
  • Cathedral setting
  • Halo setting
  • Side-stone setting
  • Flush setting

And many others, most of which are variations or combinations of the ones above.

Side-stone settings and settings with small melee diamonds across the surface of the ring, such as channel and pave settings, can look great on a lot of rings but tend to take away from the very point of getting a 3-carat diamond – they can distract from it. Still, this is a matter of personal preference.

As for the stone’s setting, most options can be more or less divided into two categories:

  • Open and exposed settings
  • Closed and protective settings

Both have their pros and cons with 3-carat diamonds.

3 carat solitaire ring

3.27 carat diamond in 4-prong setting. See details here.

The very purpose of getting such a large stone is for it to catch other people’s attention, to be noticeable, and to sparkle as brilliantly as possible. Open settings such as Prong and Solitaire achieve this very effectively. The drawback of these settings, however, is that they don’t protect the stone enough – every knock on a hard surface or every drag on a shirt’s sleeve can potentially damage an exposed and unprotected diamond.

Double halo 3 carat ring

Double halo 3 carat ring. See details here.

On the other hand, protective settings such as Bezel or Halo settings can keep your 3-carat diamond safe through a lot of accidental knocks that’d otherwise scratch and damage it. The trade-off here is that you will be sacrificing some of the diamond’s brilliance and beauty but offering greater protection for the stone.

At the end of the day, the choice is mostly subjective although you might want to consider your lifestyle and what situations you’ll be bringing the diamond in.

What Metal Should You Go for With A 3-Carat Diamond Engagement Ring?

The metal you choose for your 3-carat diamond engagement ring won’t be determined so much by the diamond’s size, but rather by its color and your preferences.

For example, if you’ve chosen a diamond that’s slightly lower on the color scale, probably to cut down its budget, then going for yellow gold is probably your best bet. As most colorless diamonds’ color hues are typically yellow or brown, yellow gold can effectively mask these imperfections and make it look as if the diamond is completely colorless and is just reflecting the gold’s color.

If your diamond is near- or fully-colorless, however, you don’t need to worry about such considerations. Whether you choose yellow gold or rose gold, or white metals such as platinum and white gold, they all would look great with a high-quality 3-carat diamond. So, it all comes down to your personal preferences again.

In general, rose gold is viewed as the more romantic and feminine option, yellow gold – as the classic and traditional choice, while white metals are more contemporary and formal. Platinum is the strongest of the precious metals and is considered to be secure choice for such an important purchase.

What Price Range Is Your 3-Carat Diamond Engagement Ring Going to Fall In?

The carat size of the diamond is the biggest determining factor for its prize. However, the cut, clarity, color, and other factors can play a role as well so the prices you’ll see can vary drastically.

3 carat diamond prices

Different prices for 3-carat diamonds depending on the 4Cs. See more here.

For a 3-carat diamond, the price can range can go from anywhere between $19,000 and $95,000, with some going north of $100,000. Generally, however, you should be able to find some good options in the $20,000 to $30,000 range such as this 3.01 Carat K-VS1 Excellent Cut Round Diamond Six Prong Wire Basket Engagement Ring – its only downside is its color which is down in the K color grade but that’s an easy compromise to make for a well-priced 3-carat diamond. Even with a color grade that’s a couple of points higher, such a ring still shouldn’t go above $30,000.

Where Can You Compromise to Get A Lower Price?

With smaller diamonds, usually in the 1 to 2-carat range, compromising with the clarity or color is the way to go. Another good idea sometimes is to compromise with the carat weight and to compensate with side stones or pave settings – this is a good way to lower the overall cost of the ring and still end up with a gorgeous-looking jewel.

With 3-carat diamond engagement rings, you can sometimes find excellent diamonds at a slightly lower price point if you drop below the 3-carat mark and opt for something that’s around 2.70 to 2.90. It’s not guaranteed that these will be lower in price, as other factors can come into play.

For example, the screenshot below compares two similar diamonds, but what stands out is that the 2.90 carat stone is much more expensive than the 3-carat stone. Other factors, such as fluorescence, polish, symmetry, table and depth, are what’s driving the difference in price.

2.90 diamond price

See more similar diamonds here.

It’s also best not to compromise on Clarity when it comes to such large stones – while some minor inclusions can be ignored in 1 to 2-carat diamonds, every small blemish is visible in 3-carat diamonds. Going below the VS1-VS2 clarity range is usually not a good idea either.

The one area you can compromise without too many consequences is Color. The G to J range (or G to I, especially) is usually the recommended color range for the best value for money. However, dropping to the K or L color grades can also be acceptable with the right color metal and setting.

Yellow gold 3 carat diamond

Yellow gold tends to complement/hide color in diamonds. See this customer ring here.

As mentioned above, you could choose a diamond lower on the color scale, and mask or complement its yellow tints with a yellow or rose gold setting.

Other Ways to Manage Your Budget

Lab grown diamond

Lab-grown diamonds are indistinguishable from earth-mined stones. See more here.

A very good alternative to natural 3-carat diamonds is lab-grown 3-carat diamonds. Many people are still somewhat hesitant to consider lab-grown diamonds but the technology with which they are grown today ensures that they are indistinguishable from their natural-grown counterparts.

In fact, lab-grown diamonds have fewer-to-no inclusion or blemishes in them, as they haven’t spent millions of years in the volatile environment of the Earth’s crust. So, their clarity is better than that of natural diamonds. And with an average price that’s around 3x times lower than that of similar natural diamonds, lab-grown diamonds are a great way to get a big 3-carat diamond without breaking the bank.

See lab-grown diamonds here

How to Buy A 3-Carat Diamond Engagement Ring

Now that the basics are out of the way, let’s go over the buying process. Where you buy your diamond ring is almost as important as the type of ring you’re buying and there are lots of things to consider here as well.

What certificates should you be looking for?

There are many prominent Diamond Certifications you can look out for. Most of them certify these precious stones based on the same or a similar set of principles. Plus, even the most trustworthy certificates tend to have some blind spots (such as ignoring the color or location of a diamond’s inclusions as a contributing factor to its clarity grade).

Some certificates are more trustworthy than others, however, and there are vendors that will try to offer you some completely faux “certificates.” So, the general rule of thumb is to look for any of the following certificates:

If the diamond you’re looking at is certified by any of these institutions, you can rest assured that its grades are accurate and you’ll be getting your money’s worth.

Do keep in mind that just looking at a certificate is not enough to properly judge a diamond, however, and you’ll need to look into the stone’s properties some more. GIA and AGS are generally recognized as the two most trustworthy institutions but even their certificates don’t offer a complete picture for each diamond.

What additional conditions, perks, and clauses should your purchase include?

When buying a diamond engagement ring, the quality of the jewelry piece should be your main concern. It shouldn’t be your only concern, however, and there are other parts of the transaction to pay attention to.

Different jewelers will offer different conditions and features as part of the purchase but the must-haves you should always look for include:

  1. A money-back guarantee. Especially vital for online shopping, a money-back guarantee is important even for brick-and-mortar jewelry stores. This gives you the freedom to inspect the diamond ring in person and with an independent expert before deciding to hold on to it.
  2. Free shipping with insurance. If you’re purchasing your ring online or if you’re ordering a bespoke ring for a later date, getting free shipping and insurance is a great boon. This will cut down your costs and ensures that, should an accident happen during the shipping process, it won’t be at your expense.
  3. Free or discounted annual check-ups, resizing, repair, and other such services. Diamond rings can last for decades but they need care. And a lot of that care can’t be done at home – a specialist’s touch is needed from time to time. Such diamond care can be expensive so it’s very convenient to get free or discounted future check-us, repairs, resizing, and other services as a part of your purchase.
  4. Different payment options. Buying a 3-carat diamond engagement ring can be expensive so it’s usually worth it to look for a jeweler that offers varying and convenient payment options.

Check both online and offline

A big question for when you’re purchasing a diamond engagement ring is which vendors you can trust. Many people still view online vendors as unviable options because you can’t really inspect the rings and diamonds personally before making a purchase.

Except – you can.

Reputable online vendors such as James Allen, Blue Nile, and Brian Gavin offer many perks but the three most important ones are:

  • Huge collections that overshadow the inventory of most on-location jeweler shops.
  • Excellent 3D, HD and 360o representations of their diamonds and rings so that you can see exactly what you’re purchasing.
  • Comprehensive return policies so that you can get a refund or exchange your ring if it doesn’t match your expectations.

All that being said, there’s definitely a benefit from shopping in person – being able to see a diamond ring live, from several different angles, and under different lights can give you a better idea as to what you’re buying. Just make sure that the vendor you’re visiting is reputable and you’re not paying for overvalued jewelry.

In Conclusion

To wrap up, the perfect budget-friendly and value-for-money parameters of a 3-carat diamond engagement ring are usually considered as:

  • An Excellent grade cut on the GIA or AGS scale
  • A VS1 or VS2 clarity grade
  • A G to I color grade

The features of the ring itself are usually subjective and up to your preferences. From there on, as long as you’ve picked a good diamond dealer to work with, you should rest assured that you’re making a good purchase.

If you’re looking for different sized diamonds, check out our comprehensive guides on 1-carat diamonds and 2-carat diamonds.

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