9 Carat Marquise Diamond Ring

Ultimate Guide To Buying A Nine Carat Marquise Diamond


9 carat marquise diamonds are a beautiful choice – their shape gives them unparalleled elegance and the incredible flashes of sparkling light they deliver are stunning.

Marquises are one of the less common choices for a 9 carat diamond ring, which means that there may not be a huge selection available when you are looking.

However, that doesn’t mean that you should just settle for the first 9 carat marquise you see. This guide will help you avoid sub-par stones and ensure you get a beautiful and brilliant four carat marquise that will be the perfect centerpiece for your ring.

9 carat marquise diamonds header image

How much do 9 carat marquise diamonds cost?

9 carat marquise diamonds are extremely rare, so the price of an individual stone will depend on the 4 C quality factors, as well as how well the stone has been shaped.

It’s likely that the price could range from $150,000 for a diamond with low color and clarity (e.g. SI2 clarity, K color) all the way to over $800,000 for a diamond with high colour and clarity (e.g. FL clarity, D color)

It’s important to recognise that at this carat weight, there can be considerable differences between individual stones with similar specs on paper, so each stone really does need to be assessed on its own basis.

9 carat marquise diamond size


Marquise diamonds are one of the ‘spreadiest’ shapes of any diamond, which means that for a given carat weight, they appear larger than other shapes.

A typical A typical 9 carat marquise diamond may be around 21.6mm × 10.8mm × 6.59mm.

Here’s how it looks compared to a 7 carat and an 9 carat:

9 carat marquise diamond size comparison

One important thing to understand when you are looking at marquise diamonds is that carat weight is a measure of weight rather than size.

Carat weight is therefore spread out throughout the volume of the stone ie. length, width and depth.

This can mean that two 9 carat diamonds can actually appear very different sizes when set into a ring and viewed from the top.

The benefit of this for marquise diamonds is that a 9 carat marquise will ‘face up’ significantly larger than other pointed shapes like a 9 carat pear shaped diamond ring and much larger than squarer shapes like a 9 carat heart diamond ring.

9 carat marquise diamond L/W ratio

Length-width ratio is, unsurprisingly, the ratio between the length and the width of a diamond:

9 carat marquise diamond length width ratio

This can hugely change what an marquise cut diamond looks like

For smaller marquise diamonds, I usually recommend a L/W ratio of between 1.75 and 2.25, as these all deliver a pleasing shape and should face up at a good size for their carat weight:

9 carat marquise diamond length width comparison

However, for higher carat weights, a longer stone can look too large, and you may find that a stone at around 1.75 length-width ratio looks better on the finder than a more elongated stone.

Lower L/W ratio marquise diamonds are also generally priced lower that higher L/W ratios, as they use more of the rough diamond (which means less needs to be wasted) and there are more of them available (law of supply and demand coming into effect). 

Watch out: bow tie effect

One thing to watch out for with higher carat weight marquise diamonds is that the ‘bow tie’ effect may be more noticeable.

The bow tie is an unappealing dark band that can run across the center of some marquises:

9 carat marquise diamond bow tie effect

This effect is often more noticeable on shallower stones with a high L/W ratio, as the light is reflected off the bottom of the stone (the pavilion facets) at the wrong angle to be reflected back to your eye, causing the dark band where light is lost.

While it’s not uncommon for a marquise to have some bow tie, The best way to avoid is it to ensure that you have access to high quality 9 carat marquise diamonds which have been cut to avoid the bow tie, and to specifically look for it when reviewing your options.

9 carat marquise diamond color

As you likely know, diamond color is graded on a GIA-developed scale from D to Z, although most diamonds used in jewelry fall into the D to M range:

9 Color scale

Higher carat weight diamonds tend to show up color more easily than smaller stones, especially in the corners where they sparkle less.

If you want to ensure your diamond doesn’t have a yellow tint, it’s important to try and keep the color as high up the scale as possible.

On the other side of the equation is the effect color has on price.

In most shapes, the price difference between an H color, I color and J color diamond can be significant,

With a 9 carat marquise, the color grade you choose can be dependant on the color of the ring setting you are going to pair the diamond with. If you are choosing a white colored setting (platinum or white gold), then I color delivers a good balance of white appearance and value.

However, if you are choosing a yellow gold setting, then you can reduce the color of your diamond to J without it looking yellow, as it will still look white compared to the warm tones of the setting.

9 carat marquise diamond color recommendation

9 carat marquise diamond clarity

Clarity is a measure of the presence of inclusions (or flaws) within a diamond.

The clarity scale runs:

9 GIA diamond Clarity scale

Marquise diamonds are a brilliant cut, which means that they are optimised to reflect light back from the bottom of the stone in the form of brilliant sparkle. This can mean that inclusions can be difficult to see under the facets, which is a good thing!

However, at the same time their elongated shape means they have a large ‘table’ (the flat area on the top of the diamond), which can mean that inclusions located here are easier to see. At higher carat weights, this issue is compounded as a bigger diamond means a bigger window where flaws can be seen.

A good starting point for 9 carat marquise diamond clarity is SI1:

9 carat marquise diamond clarity

However, depending on the diamonds that are available at the time you are looking, you may need to increase this to VS2, or even higher, to ensure that the diamond is ‘eye clean’ and no flaws can be seen.

Best Place To Buy a 9 Carat Marquise Diamond Ring

For smaller carat weights, my recommended retailers are usually James Allen or Brilliant Earth. Both offer a huge selection of stones and high quality service.

Neither retailer offers 9 carat diamonds, however, so my strong recommendation is to find a reputable diamond dealer who can assist you with sourcing your diamond. My recommendation is Alon Mor at The Diamond Oak.

Alon is a third generation diamond dealer who specialises in higher carat weight diamonds and puts a huge emphasis on personalised service and finding the right stone for each person.

I like this review of his service – it’s worth a read to understand just how special buying a diamond can be.

If you’d like to feel as special as the person in this review, I’d recommend getting in touch with Alon. Let him know you heard of him through Ringspo and he will go above and beyond to make the experience even more special.