<img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=1764711180450349&amp;ev=PageView&amp;noscript=1">

Diamond Shape: The Ultimate Guide

Posted by Burrells on Sep 10, 2018 9:58:28 AM


Choosing a diamond can be overwhelming. Being faced with rows and rows of sparkling stones and trying to make an objective decision is not an easy thing to do. After all, the purchase of a diamond is not an everyday event.

You’re likely to be choosing a stone or piece of jewellery for someone who means a lot to you. This combined with a significant financial investment can add layers of complexity and emotion to the buying process.

But there is a way to reduce your stress levels and buy a diamond that you will enjoy for years or decades to come. And that’s to spend a little time and research learning the basics of diamond shape and cut.

Once you have the knowledge to understand diamonds better, the buying experience is transformed. Suddenly you have the power to make an informed decision.

Our guide to diamond shape and cut will help you slice through the complexity and find the perfect stone.


What is the Difference Between Diamond Shape and Cut?

Confusingly these terms are often used interchangeably, but they have very different meanings that are vital to understand if you want to get to know diamonds better. Diamond shape refers simply to the outline shape of a diamond.

So, a heart shaped diamond is, quite intuitively, a diamond which has been crafted into the shape of a heart. Cut can sometimes be used in place of shape when describing the overall appearance of a diamond.  

The diamond cut is where things get a little more complex. Diamond cut takes into account the facets, dimensions and reflective qualities of a gemstone. A diamond cut could be shallow, deep, brilliant or ideal. It is the quality of the cut that elevates the natural radiance of a diamond.

It’s sensible to first think about the shapes that appeal to you before diving deeper into the impact of cut on that desired shape.


Diamond Length to Width Ratio

When exploring diamond shape you may also find information on diamond ratio. This number is the length of the diamond divided by its width.

This number helps to determine how proportionate a diamond is in reference to its shape. We will discuss the ideal ratio for each of the diamond shapes we explore.


10 most popular Diamond Shapes

Now, it’s time to investigate 10 of the most popular diamond shapes around. You might even discover your favourite diamond shape in our ultimate guide.


Round Brilliant Cut Diamonds

This classic diamond shape remains an incredibly desirable style of diamond, with 75% of the world’s jewellery diamonds being shaped into a round brilliant cut. They also represent some of the most expensive diamonds in the world. But just why is this look so popular?

The surge in round brilliant diamonds can be traced back to a seminal work by Marcel Tolkowsky, Diamond Design: A Study of the Reflection and Refraction of Light in Diamond.

This book described the exacting angles of a round brilliant cut diamond to provide astonishing brilliance. Round brilliant cut diamonds reflect the light more effectively causing intense sparkle.

This could be why they are set apart from other diamond shapes. Any diamond shape other than a round brilliant cut is described as a fancy shaped diamond.

Round brilliant cuts have 58 facets (or 57 if the bottom point, the culet, is excluded). There are 33 facets on the crown (the top half of the stone), and 25 on the pavilion (the bottom half of the stone, below the girdle, which is the widest part of a diamond).


Diamond Buying Advice

A poorly-cut round brilliant diamond will appear significantly flatter and duller than a well-cut one. It’s useful to get advice from an expert jeweller if you are unsure on the quality of the cut.


Buy a Round Brilliant Cut Diamond If...

You want a timeless stone with brilliant shine for an engagement ring, earrings or a necklace.


Princess Cut Diamonds

The princess cut is the most popular of the fancy diamond shapes. It was developed from older barion and quadrillion cuts in the 1970s. It’s traditionally a square or sometimes a rectangular shaped diamond created from an inverted pyramid with bevelled sides.

It provides the greatest brilliance of all the fancy diamond shapes, although it is not a match for a round brilliant cut.

The princess cut is a popular modern cut for engagement rings and is generally held in a setting with claws at each corner. This can be useful for hiding inclusions or flaws.

The princess cut also offers a more budget-friendly option compared to some diamond shapes. This is because less carat weight is lost when cutting from a rough diamond which has a cubic crystal structure. You get more diamond for your money, but not as much light return as with other diamond shapes. 

Princess cut diamonds have either 57 or 76 facets, with a ratio of between 1.0 and 1.05.


Diamond Buying Advice

Slightly rectangular princess cut diamonds tend to look more pleasing to the naked eye. Look at several different ratios to find out which feels most comfortable to you.


Buy a Princess Cut Diamond If...

You want a modern looking engagement ring with impressive brilliance.


Emerald Cut Diamonds

The emerald cut is a traditional fancy shaped diamond defined by a large flat table, truncated corners, and step cuts. They are usually rectangular in shape.

Although the emerald cut doesn’t have the dazzling brilliance of some other cuts it does have a beautiful interplay of light and shadows that is an excellent way to show off the clarity of larger stones.

Emerald cut diamonds have been around for a long time, but they found real popularity in the Art Deco period and for that reason carry a vintage vibe that is very appealing to some diamond lovers.

The number of facets in an emerald cut can vary but there are usually 57. A desirable ratio is between 1.30 and 1.60 with 1.50 considered the ideal proportion.


Diamond Buying Advice

Because of the flat table, inclusions can be very visible in an emerald cut diamond. It’s recommended that buyers choose high clarity grades of stone to achieve a seamless, clean look.


Buy an Emerald Cut Diamond If...

You love the look of vintage rings with an Art Deco influence.


Cushion Cut Diamonds

The cushion cut diamond is a square cut, fancy diamond with softly rounded corners that give the appearance of a cushion or pillow.

The precise cut, which was developed from the more traditional ‘old mine cut’, has been refined over the years to create precise refraction of light that adds to its brilliance. Older cushion cut diamonds may have a chunkier finish and provide less fire.

With modern techniques allowing for greater refinement and brilliance, there is generally more variation in cushion cut diamonds than any other major diamond shape. Because of this diversity, they offer more options for buyers to explore in terms of diamond cut and design.

Cushion cut diamonds usually have 58 facets. Square cut cushions have an ideal ratio between 1.00 to 1.05 while rectangular cushion shapes may be 1.10 or more.


Diamond Buying Advice

The facets in a cushion cut diamond allow for greater dispersion of light than other shapes, meaning they are better at hiding inclusions. This makes the shape a good choice for a diamond that has small imperfections.


Buy a Cushion Cut Diamond If...

You want a classic diamond shape with room for personal flair.


Asscher Cut Diamonds

The asscher cut shares similarities with the emerald cut. It has the same flat table and truncated corners.

The asscher cut usually has a square shape and showcases a slightly smaller table and more layered facets than an emerald cut however. This gives it a more dazzling appearance.

The Asscher cut was first introduced to the world in 1902 by the Asscher brothers of Holland, and over a hundred years later has again become a popular choice with only a few small refinements. The Asscher, like the emerald, showcases the clarity and colour of the stone so can’t be relied upon to mask imperfections.

Asscher cut diamonds typically have 58 facets with a ratio between 1.00 and 1.05.


Diamond Buying Advice

The Asscher cut diamond enjoyed its heyday in the 1920s and therefore it’s a good cut to look out for if your preference is an antique stone or ring. 


Buy an Asscher Diamond If...

You are drawn to an emerald cut diamond but want a little more dazzle. 


Pear Shaped Diamonds

Classic, simple and elegant, the pear shaped diamond is a traditional cut that feels timeless. Crafted in a teardrop shape, the pear shaped diamond shares elements from both the round brilliant, and marquise shapes.

Symmetry is key to a high-quality pear shape, so as to provide an even refraction of light.

Pear shaped diamonds in rings are traditionally worn so that the tip of the pear faces the wearer. This fancy shape has a long history, dating back to the 1400s when the first diamond polishing wheel was invented by a Flemish diamond cutter.

Made up of 58 facets, pear shaped diamonds should have a ratio between 1.50 and 1.70.


Diamond Buying Advice

The unique pear drop shape can sometimes cause a ‘bow-tie’ effect where light passes through the stone and casts a shadow across the width of a diamond, often in the centre. This effect forms a dark shape reminiscent of a bow-tie, hence the name.

The bow-tie effect is usually seen in fancy cut diamonds like pear, oval and marquise. It can be reduced by careful design but it’s something to be aware of. 


Buy a Pear Shaped Diamond If...

You want an unusual stone that still feels utterly timeless. 


Oval Cut Diamonds

The oval diamond takes elements of the pear shape and round brilliant cut diamond to create a unique shape that is perfect for showing off larger stones. It offers excellent brilliance and the elongated shape can make stones appear larger than other cuts that are the same carat weight.

The oval cut makes an excellent central stone in an engagement ring and can help to elongate shorter fingers. An oval diamond also combines some of the best features from round brilliant and fancy diamonds.  

An oval cut diamond usually has 58 facets with a ratio between 1.33 and 1.66.


Diamond Buying Advice

Ratio has a significant impact on the brilliance of oval cut diamonds. A longer shape (and larger ratio) may look better with shorter fingers but a rounder oval (and smaller ratio) can prevent the ‘bow-tie’ effect.


Buy an Oval Cut Diamond If..

You want some of the dazzle of a round brilliant cut with a more unique shape.


Heart Shaped Diamonds

The ultimate symbol of love, the heart shaped diamond is a stone for romantics. A good heart shaped diamond should be balanced, symmetrical and have a clearly defined tip.

An overly elongated or wide heart can lose some of its crispness. Heart shaped diamonds are versatile and look great set into pendants, rings, and earrings.

The heart shape is a premium and skilled cut, and an unusual one. This means that they can hold their value and be more desirable than more readily available fancy shapes. The quality of the curved cut and finish will determine how well the diamond refracts light and the brilliance of the stone.

Heart shaped diamonds can have between 56 and 58 facets with an ideal ratio of 0.90 to 1.10.


Diamond Buying Advice

Heart shaped diamonds look best in 1 carat stones and above to achieve the fullness of shape that this cut requires. However, careful placement of prongs can help to define a heart shape in smaller stones.


Buy an Heart Shaped Diamond If...

You are a romantic who likes to show off their softer side.


Radiant Cut Diamonds

The Radiant cut diamond is a relatively recent addition to the fancy diamond family. Created in 1977 by Henry Grossbard of the Radiant Cut Diamond Company, it is a hybrid style designed to bring brilliance to square and rectangular shaped stones.

It combines the classic lines of the emerald cut with the brilliance of a princess cut to create a modern and dazzling shape.

The radiant cut was a highly popular shape throughout the 1980s and remains a desirable choice for buyers who value brilliance and geometric style. The sparkle of the radiant cut comes from the high number of facets which refract light beautifully.

The radiant cut diamond has 70 facets and for square stones a ratio of between 1.00 and 1.05. Rectangular ratios will be higher – up to 1.50.


Diamond Buying Advice

The radiant cut is a great choice for stones with a number of visible inclusions or a less desirable colour. It is one of the best shapes for bringing the best out of diamonds that would be more exposed in other square or rectangular cuts.


Buy a Radiant Cut Diamond If...

You want a diamond that combines a modern shape with show-stopping brilliance.


Marquise Diamonds

The marquise is a diamond with a faintly scandalous backstory. It’s said to have come about when requested by King Louis XV, who wanted a jewel that mirrored the mouth of his mistress, the infamous Madame de Pompadour.

The elegant shape is flattering and delicate, elongating the shape of smaller fingers.

Due to its shape, the marquise is one cut that can suffer from the ‘bow-tie’ effect and therefore it’s essential to choose a stone that is not too shallow. A well-cut marquise can offer a good level of brilliance and fire.

A marquise diamond has 56 to 58 facets and should have a ratio between 1.85 and 2.10.


Diamond Buying Advice

The marquise is a great shape for making the most of carat weight, with its elongated shape making stones appear bigger. It’s a good choice for those wanting to make the most of their budget.


Buy a Marquise Diamond If...

You want an elegantly shaped diamond with a fascinating history.


Want to learn more?

We hope you’ve found this article helpful. If you have any questions, we have over 40 years of diamond expertise and are always available to help.

You can get in touch with one of our experts here, and you can view our beautiful diamond collection in-store.


You Might Also Like...

The Ultimate Guide to Finding an Engagement Ring

Certified Diamond vs Non-Certified Diamond Engagement Rings

Most Popular Engagement Ring Settings (Pros & Cons)


Subscribe to Email Updates

New call-to-action
New Call-to-action