The Complete Guide to Diamond Shapes and Cuts: What Really Matters When Choosing Your Perfect Diamond
By Amr Ramadan DGA, Hatton Garden Jeweller
All You need to know about the Diamond Shape vs. Diamond Cut
The most common question I hear in my Hatton Garden showroom isn’t about the 4Cs or certification, it’s “What’s the difference between all these shapes?” People walk in knowing they want a diamond, but feeling overwhelmed by the sheer number of options available.
This confusion is understandable. The diamond industry has evolved significantly since I began my training at Gem A London ten years ago.
What started with just a few traditional shapes has expanded into dozens of variations, each with its own characteristics and considerations.
After working my way through major Hatton Garden stores as a gemologist and sales manager, and now running Mouza Fine Jewellery, I’ve observed that most people approach shape selection backwards.
They look at photos online, pick something that seems appealing, then try to learn about it. But diamond shapes aren’t just about appearance, they’re about light performance, durability, and how the stone will look on the hand that wears it every day.
Whether you’re considering natural diamonds with their geological heritage or exploring lab grown diamond rings with their modern precision, understanding shape fundamentals is crucial.
Each shape interacts with light differently, has different structural considerations, and requires different evaluation criteria beyond the standard 4Cs.
The goal isn’t to memorise every technical detail, it’s to understand what makes each shape unique so you can make an informed choice that you’ll love for decades to come.
Understanding Diamond Shape vs Cut Quality: Why This Matters More Than You Think
Here’s something that confuses almost everyone: diamond “shape” and “cut” aren’t the same thing, though people use them interchangeably all the time. Shape is what you see when you look down at the diamond round, oval, square, whatever.
Diamond Cut is about how well the diamond has been faceted to interact with light.
This distinction matters because you might find a gorgeous emerald shape diamond that’s been cut poorly, or a princess shape that’s been cut brilliantly.
The shape gives you the style, but the cut quality determines whether your diamond will sparkle or look dull.
From my experience working with both natural and lab grown diamond rings,
I’ve seen how this confusion leads people to focus on the wrong things.
They’ll spend ages deciding between a cushion and an oval, then barely consider whether either stone is actually cut well enough to be beautiful.
What Happens When Light Hits Your Diamond
Think of a diamond like a complex mirror system. When light enters a well-cut stone, it bounces around inside, hitting different facets before shooting back out towards your eye. That’s what creates all that sparkle and fire. But if the angles are wrong if the diamond’s been cut too shallow or too deep the light just leaks out the sides or bottom, and you’re left with a dull stone that looks more like glass than a diamond.
I’ve seen people spend £15,000 on a diamond that barely sparkles because they focused on getting a bigger stone rather than a well-cut one. Trust me, a smaller diamond that’s cut beautifully will always look more impressive than a larger one that’s been cut poorly.
Round Brilliant Diamonds: Still Popular for Good Reason
About 45% of the diamond engagement rings I sell are round brilliants, and there’s a good
reason for that.
The round brilliant cut has been perfected over decades to maximise light return.
When you see a diamond that just seems to glow from within, it’s probably a well-cut round brilliant.
What to Look for Beyond the 4Cs
When you’re considering a round brilliant, here’s what really matters:
Crown and pavilion angles: The crown angle should ideally be between 34-35 degrees, and the pavilion angle around 40.6-41 degrees. These aren’t just random numbers, they’re the result of decades of research into how light behaves in diamonds. If these angles are off, your diamond won’t perform properly.
Table percentage: This should be between 54-59%. The table is the flat top of the diamond, and if it’s too big or too small, it affects how light enters and exits the stone.
Depth percentage: Look for 58-61%. Too shallow and light leaks out the bottom; too deep and the diamond looks smaller and darker.
I always educated my clients about these measurements.
Any reputable Hatton Garden jeweller should have them readily available. If they don’t, or if they seem reluctant to share them, that’s a red flag.
The GIA grades round brilliant cuts from Excellent down to Poor. I only recommend Excellent or Very Good grades.
Yes, they cost more, but the difference in beauty is dramatic. I’ve had customers come back years later thanking me for pushing them towards the better cut grade.
Princess Cut Diamonds: Modern Brilliance in a Square Package
Princess cuts used to be the second most popular choice for engagement rings, especially among clients who want something classic but still brilliant.
They’re essentially the square version of a round brilliant, with similar light performance but a completely different personality.
What You Need to Know About Princess Cuts
The thing about princess cuts is that they’re more vulnerable than rounds because of those sharp corners. I always recommend protective settings with V prongs that cover the corners or bezels that wrap around them.
I’ve seen too many chipped princess cuts from people who didn’t realise how delicate those points can be.
Length-to-width ratios: For a true square look, stay between 1.00 and 1.05. If you prefer a slightly rectangular shape, 1.05-1.10 can look elegant, but beyond that, you’re getting into a different aesthetic entirely.
Depth considerations: Princess cuts can handle a bit more depth than rounds, anywhere from 68-75% is acceptable.
The deeper cuts often show more fire, which some people love.
When you’re looking at princess cuts, pay attention to how the light moves across the surface.
A well-cut princess should show a pattern of light and dark areas that creates visual interest without any dead spots where the diamond looks dull.
Emerald Cut Diamonds: For Those Who Appreciate Understated Elegance
Emerald cuts are completely different beasts. Instead of trying to maximise sparkle, they create what we call a “hall of mirrors” effect long, elegant flashes of light that emphasise the diamond’s clarity and colour rather than its fire.
The Emerald Cut Personality
I find that emerald cuts appeal to people who have confidence in their own style.
They’re not trying to be the sparkliest thing in the room; they’re making a statement about elegance and refinement. Think Grace Kelly rather than Kim Kardashian.
What to focus on when choosing an emerald cut:
Table and depth percentages: Look for table percentages between 61-69% and depth percentages between 60-68%. These proportions create the best balance of the hall-of- mirrors effect without making the diamond look too glassy.
Step-cut faceting: Unlike brilliant cuts, emerald cuts have long, parallel facets. This means inclusions and colour tints are much more visible.
I usually recommend going up a grade or two in both clarity and colour compared to what you might choose in a round brilliant.
Length-to-width ratios: Classic emerald cuts are around 1.30-1.50, but this is really about personal preference. Some people love a more square emerald (around 1.20), while others prefer a longer, more elegant rectangle (up to 1.70).
The beauty of emerald cuts is in their subtlety. They don’t scream for attention, but when someone notices them, the effect is striking.
Oval Diamonds: The Best of Both Worlds
Ovals have become incredibly popular in recent years, and I understand why. They give you the brilliance of a round diamond but with an elongated shape that can make fingers look longer and more elegant. Plus, they often appear larger than a round diamond of the same carat weight because of their greater surface area.
The Oval Advantage and What to Watch For
The bowtie effect: This is the big thing to watch for with ovals. Most ovals will show some degree of a dark area across the middle that looks like a bowtie.
A little bit is normal and even adds character, but if it’s too pronounced, it makes the oval diamond engagement ring look dull.
When I’m selecting ovals for clients, I always view them in person or through high-quality videos. You can’t judge a bowtie effect from a photograph.
Length-to-width ratios: Most people prefer ratios between 1.35-1.50.
Below 1.20 and the oval diamond starts looking too round; above 1.60 and it can look too narrow and elongated and loses its oval shape.
Depth and table considerations: Look for depth percentages between 58-63% and table percentages between 53-61%. These ranges help minimise the bowtie effect while maximising brilliance.
I’ve noticed that ovals photograph beautifully, which might explain some of their recent popularity on social media.. They have this elegant, timeless quality that works with both vintage and modern engagement ring settings.
Cushion Cut Diamonds: Vintage Charm with Modern Performance
Cushion cuts are like the comfortable, lived-in jeans of the diamond world they have this soft, romantic quality that many people find irresistible.
They’re essentially squares or rectangles with rounded corners, and they come in many varieties: traditional cushions, modified cushions and heart and arrows cushions.
Traditional vs Modified Cushions
Traditional cushions have larger facets and tend to show more fire (those rainbow flashes), while modified cushions have additional facets that create more sparkle. Neither is better than the other it’s about what appeals to you.
What to look for in cushion cuts:
Square vs elongated: Square cushions (ratios 1.00-1.10) have a classic, balanced look. Elongated cushions (ratios 1.15-1.50) can be stunning and often appear larger for their carat weight. Must add they have been increasing in popularity recently.
Depth considerations: Cushions can handle more depth than rounds anywhere from 62- 68% is fine. The deeper cuts often show more character and fire. The crushed ice vs chunky facet debate: Some cushions show a “crushed ice” pattern with lots of small sparkles, while others show larger, chunkier flashes.
This is purely personal preference, but I find that people tend to have strong opinions once they see both styles side by side.
Elongated Cushions: A Modern Twist
Elongated cushions have become particularly popular recently. They offer the soft, romantic feel of a traditional cushion but with a more modern, elongated silhouette. The key things to watch for are the same as with ovals potential bowtie effects and ensuring the proportions look balanced rather than too stretched.
Historical and Specialty diamond Cuts: For Those Who Want Something Different
Old Mine Cut: A Piece of History
Old mine cuts are the predecessors to modern round brilliants.
They were cut by hand in the 1800s and early 1900s, so they have this charming, slightly irregular quality that modern precision cutting can’t replicate.
If you love vintage jewellery and want something with real historical character, old mine cuts are worth considering.
They typically have higher crowns, smaller tables, and larger culets (the small facet at the bottom) than modern cuts.
This gives them a different kind of beauty less brilliant than modern cuts but with more fire, character and a romantic, candlelit glow.
Ashoka Cut: Modern Innovation
The Ashoka cut is a relatively new, patented cut that combines elements of emerald and cushion cuts.
It has 62 facets compared to the 57 of a traditional emerald cut, which gives it more brilliance while maintaining that elegant, elongated silhouette.
Ashoka specifications: These diamonds typically have length-to-width ratios between 1.40-1.60 and depth percentages around 60-65%.
Because it’s a patented cut, you’ll only find true Ashokas from authorised dealers, and they command a premium.
The appeal of Ashokas lies in their uniqueness. They’re rare enough that most people won’t immediately recognise the cut, but elegant enough to be timelessly beautiful.
Pear Cuts: Elegant and Unique
Pear cuts combine the brilliance of rounds with the elegance of marquise cuts. They’re distinctive without being too unusual, and they can be worn with the point towards the finger or towards the hand, depending on preference.
What to watch for: Like ovals, pears can show bowtie effects.
The ideal length-to-width ratio is usually between 1.45-1.75, with most people preferring around 1.55-1.65. The point should be well-defined but not too sharp, and the shoulders (the curved sides) should be symmetrical.
Marquise Cuts: Dramatic and Eye-Catching
Marquise cuts are definitely statement pieces. They’re long and pointed at both ends, which can create a dramatic, regal look.
They also tend to appear larger than other shapes of the same carat weight because of their elongated form.
Considerations: Bowtie effects are common, and the points are vulnerable to chipping. Length-to-width ratios typically range from 1.75-2.25, with most people preferring around 2.00.
Heart Cuts: For the Romantic
Heart cuts are obviously symbolic, but they’re also quite challenging to cut well. The two halves need to be perfectly symmetrical, and the cleft (the indentation at the top) needs to be well-defined without being too deep.
If you’re considering a heart cut, I’d strongly recommend seeing it in person.
They can look quite different from photographs, and the quality of the cutting makes a huge difference in how recognisable the heart shape is.
How to Choose: Practical Advice from Someone Who’s Seen It All
After all these years, here’s what I’ve learned about helping people choose diamond shapes for their engagement rings:
Think About Your Personal Style
Are you classic and timeless? Round brilliants and Oval cuts might appeal to you.
More contemporary and fashion-forward? Consider radiant, elongated cushions, or even Ashoka cuts. Romantic and vintage-loving? Cushion cuts and old mine cuts could be perfect.
Consider Your Hand Shape
This isn’t a hard rule, but elongated shapes (ovals, emerald cuts, pear cuts) can make shorter fingers appear longer.
Wider shapes can balance out very long, thin fingers. But honestly, the most important thing is what you love, I’ve seen every combination work beautifully.
Budget Considerations
Round brilliants typically cost the most because they’re in highest demand and because more rough diamond is wasted in cutting them.
Fancy shapes can offer better value, with emerald cuts and Asscher cuts often being the most affordable, followed by cushions and ovals.
Lab Grown vs Natural: Does Shape Matter?
Whether you choose natural or lab grown diamond rings, the principles of shape selection remain exactly the same.
Lab grown diamonds are cut using the same techniques and to the same standards as natural diamonds. The only difference is their origin.
I’ve worked with both extensively, and I can tell you that a well-cut lab grown oval will be just as beautiful as a well-cut natural oval. The choice between natural and lab grown is about your personal values and budget, not about the quality of the cutting or the beauty of the shapes.
Working with Hatton Garden Jewellers: What to Expect
When you’re shopping for diamond engagement rings in Hatton Garden, you’re dealing with some of the most experienced diamond professionals in the world.
We’ve been the centre of London’s diamond trade for over a century, and that expertise shows.
A good Hatton Garden jeweller should be able to show you diamonds in different lighting conditions, explain the specific characteristics of each shape, and help you understand what to look for.
We should have the detailed measurements and proportions readily available, and we should be patient with your questions.
Don’t be afraid to ask to see multiple stones side by side. The differences between well-cut and poorly cut diamonds become obvious when you can compare them directly.
Frequently Asked Questions
Which diamond shape looks the largest?
Elongated shapes like marquise, oval, and emerald cuts typically appear larger than round diamonds of the same carat weight because they have more surface area.
However, a well-cut round brilliant will often look more impressive because of its superior light performance.
Do different shapes require different clarity grades?
Yes, absolutely. Step cuts like emerald and Asscher cuts show inclusions much more readily than brilliant cuts.
I usually recommend going up a grade or two in clarity for these shapes. Brilliant cuts like rounds, princess, and cushions are more forgiving and can hide inclusions better.
Which shapes are most prone to chipping?
Any shape with pointed corners or tips is more vulnerable.
Princess cuts, marquise, pear, and heart shapes all need extra care. This doesn’t mean you should avoid them, but you should choose protective settings and be mindful of how you wear them.
How important is symmetry in fancy shapes?
Very important. Poor symmetry in fancy shapes is immediately noticeable and affects both beauty and value.
This is especially critical in shapes like hearts, where perfect symmetry is essential for the shape to be recognisable.
Can I change my mind about the shape after seeing it set?
Most reputable Hatton jewellers will work with you if you’re not happy, but it’s much
better to be sure before setting.
This is why I always recommend seeing loose diamonds first, and if possible, seeing them in similar settings to what you’re considering.
Do certain shapes work better with specific setting styles?
Some combinations are more natural than others.
Solitaire engagement rings work with any shape. Halo and trilogy settings can make smaller diamonds appear larger but work especially well with rounds, cushions, and ovals.
Vintage-style settings often pair beautifully with emerald cuts and cushions.
Making Your Choice: What Really Matters
The diamond shape you choose will influence every other decision you make from setting style to budget allocation.
After many years of working with both natural and lab grown diamond rings, I’ve learned that the most satisfied customers are those who understand these fundamentals before they start shopping.
The industry continues to evolve.
New cutting techniques emerge, technology improves precision, and consumer preferences shift. But the basic principles of light performance, structural integrity, and personal preference remain constant.
Working with the best Hatton Garden jewellers means having access to expertise that goes beyond just showing you inventory.
At Mouza we understand that choosing a diamond shape for your engagement ring is about more than just picking something that looks nice in a photo it’s about finding something that will continue to bring joy for decades.
The diamond market offers more choices today than ever before. Whether you’re drawn to the mathematical precision of a round brilliant, the vintage appeal of an emerald cut, or the modern elegance of an oval, each shape has its place and its perfect match.
Take time to see different shapes in person. Understand what you’re looking at.
Ask questions about light performance, durability, and long-term satisfaction.
The right choice is the one that combines technical excellence with personal appeal and that combination is different for everyone.
Your perfect diamond shape is waiting to be discovered. With the right knowledge and guidance, you’ll recognise it when you see it.
