Imagine this: a rough diamond arrives in a workshop in Surat where a master cutter works their magic on it. The expert diamond cutting process turns the jewel into a precious object so spectacular, it’s hard to look away.
Ever wondered why one diamond may have a blinding sparkle while another might have a duller shine? The way a natural diamond is cut determines this. But what exactly does diamond cutting entail? Why is it so pivotal to the brilliance of a diamond? Let’s find out.
Why diamond cut quality matters in natural diamonds
Diamond cutting is both art and science. It’s the only part of the 4Cs of diamonds (cut, colour, clarity and carat) that’s entirely in human hands.
What are diamond cuts?
In simple terms, diamond cuts determine how a natural diamond plays with light — how it bends, reflects and refracts every beam that hits it.
This interaction is what gives a diamond its fire (those gorgeous flashes of colour), brilliance (that white sparkle) and scintillation (the ‘dance’ of light as the diamond moves).
Put another way: whether you’re choosing a wedding maang tikka or a tennis bracelet you’ll wear every day, it’s the cut that shapes the diamond’s visual personality. It’s what makes it look alive.
Why cut determines sparkle and value
How important is a diamond’s cut? Well, even a high-carat, flawless diamond can appear flat-looking if its cut isn’t up to scratch. Think of it like a perfectly cast actor with a bad script. A well-cut diamond with slightly lower grading in terms of the other Cs, on the other hand, can outshine the rest if its cut is, quite literally, on point.
The magnificence of all the princess-cut diamond engagement rings on your Pinterest board and the round brilliant-cut diamond pendants that you dream of gifting yourself someday soon is all determined, to a great degree, by how the diamonds are cut.
How diamonds are cut — from rough to refined
Behind every breathtaking diamond is a cutter, also called a diamantaire, who made dozens (sometimes hundreds) of small but very important decisions. These carefully made creative calls balance two competing priorities: to preserve a diamond’s carat weight and maximise its brilliance.
The rough stone and initial planning
When cutters evaluate a rough diamond before working on it, using state-of-the-art mapping technology and artistic intuition, they consider everything from its natural shape and internal flaws to external blemishes and potential yield (the amount of usable diamond that’s left after it’s been cut). Picture the cutter like a fashion designer, tailoring couture and cutting away excess fabric to sculpt the perfect fit.
Making the most of diamond cutting machines
How well diamonds are cut is a decision that doesn’t just affect how the jewel looks today but impacts how it may be financially valued decades down the line.
Fun fact: In the late 1900s, India accounted for about 70% by weight and 35% by (wholesale) value of the diamonds polished annually worldwide1. And it is estimated that over 90% of the world’s diamonds are cut and polished in India now2.
But how exactly are these diamonds cut and polished? What constitutes the diamond cutting process in the centres in cities like Surat?
For starters, it requires a lot of precision.
After the rough diamonds are sorted and marked, they undergo a sawing process. A specialised saw, rotating at a speed of 4000 revolutions per minute, or laser is used to cut the rough diamond into different pieces. This step, which can take up to eight hours, is followed by bruting that involves rotating one diamond against another that may also be rotating or may be stationary, resulting in the gemstone’s basic shape. The final step is polishing, where the facets of the cut diamond are polished in a way that helps the gemstone reflect and refract the optimal amount of light.
How diamond facets and proportions affect brilliance
So, what exactly makes a well-cut diamond seriously sparkle? Just ask anyone who saw the necklace Indian heiress and business magnate Isha Ambani wore to the 2025 Met Gala. Her 481.42-carat masterpiece, centred around a stunning 80.73-carat cushion-cut diamond, lit up the red carpet3. No filters or flash needed — it was all precision-cut brilliance.
The secret behind that kind of dazzle is geometry. Every facet and proportion is meticulously crafted to bounce light in all the right directions, creating fire and brilliance. Different types of diamond cuts play with light in their own ways, resulting in unique sparkles.
Faceting is the process of cutting tiny flat surfaces into a diamond. The placement, size and angles of these facets (or flat surfaces) allow light to enter the gem, bounce around and shoot off it.
There are many different types of facets and terms regarding a diamond’s cut, which are useful to know when considering buying a diamond:
Table
This refers to the large, flat top of a diamond. Size is important here — too big and light leaks out, but too small and the ‘sparkle window’ has been compromised.
Crown angle
This is the angle between the diamond’s table and the sloping facets just below it (called the crown facets). This affects how light enters and leaves the diamond, playing a key role in its dazzle.
Pavilion depth
This is the lower half of the diamond. If it’s too shallow or too deep, light escapes instead of returning to your eye, making the diamond look dull or dark.
Symmetry
A diamond’s symmetry is how precisely its facets are aligned, shaped and positioned next to each other. Even slight imperfections in positioning can cause diamond brilliance to dim. That could be why some diamonds might look a little ‘off’.
Together, these elements help shape a diamond’s ‘light signature’. Two diamonds with identical carat weight and clarity can look totally different under the spotlight thanks to their cut.
For instance, take two round brilliant diamonds: one with excellent symmetry will return light evenly across its surface, while one with poor symmetry may show dark patches, uneven sparkle or an off-centre pattern. Those tiny facet alignments make a visible difference, even to the naked eye.
How the quality of a diamond affects its value
In addition to the size of a diamond, we often prioritise its brilliance. It makes sense that the more ravishing the diamond, the more coveted it is, and so a diamond’s brilliance can be directly tied to its monetary value. Which is why it’s so important to focus on diamond cuts.
Polished diamonds larger than 0.3 carats in weight (also known as 30 points) come with a diamond grading report. This report documents key details about the gemstone — namely its origin and grading in reference to the 4Cs. While buying diamonds, never forget to enquire about reports by reputed certification bodies such as the IOD (De Beers Institute of Diamonds), IGI (International Gemological Institute) and GIA (Gemological Institute of America). All reputable jewellers will be able to offer those.
In terms of cut, the report will state a diamond’s grade — Excellent, Very Good, Good, Fair or Poor — and often include a diagram depicting its exact proportions and measurements.
Diamonds with Excellent cut grades typically fetch higher prices4, because brilliance is seen to make a diamond more beautiful and desirable5. Cut quality is factored into resale and insurance assessments6.
The difference between commercially cut and expertly cut diamonds
However, not all diamonds are cut with the same artistry. In some commercial cutting operations, the priority is often the yield over beauty, and in an attempt to get maximum carats from a gem, cut quality can be compromised.
On the other hand, expertly cut natural diamonds serve as a reminder not just of the meticulous attention and precision that was required to perfect it but also of the decades-old craftsmanship heritage and artistry involved in the diamond cutting process. This adds an extra layer of emotional power to the diamond because after all, who doesn’t love a great story?
You may see this drop first-hand: synthetic diamonds, like lab-grown ones (also called LGDs), may look OK under fluorescent store lights but fall flat in daylight. On the other hand, natural diamonds often receive more dedicated time, individual attention and care in the cutting process.
Questions to ask when evaluating diamond cut quality
If sparkle is top of your wish-list when buying or researching diamonds, keep these pointers front of mind:
Is the diamond symmetrical?
And does the diamond ‘come alive’ when you move it and hold it at different angles?
Review the diamond’s grading report
An Excellent (sometimes also called ‘ideal’) cut grade is a great sign.
How well does it reflect light?
Reputable sellers can provide brilliance or fire analysis, so don’t be shy to ask.
Let your eyes be the judge
If one diamond ‘winks’ at you more than the rest, it’s most likely been cut with serious care. Examine it in natural daylight — how a diamond appears in the sharp light of the jewellers’ could differ from how it responds to daylight.
Ask anyone who knows their gemstones — a diamond’s true sparkle is down to the art of the cutter. From navigating that delicate balance of proportions to prioritising its brilliance wherever possible, craftsmanship is what transforms a natural gem, born deep within the Earth, into a ravishing treasure. Be sure to choose wisely when it’s your turn to shop.
Sources
- GIA, The Rise to Prominence of the Modern Diamond Cutting Industry in India ↩︎
- Naturaldiamonds.com, Surat – an Agora of Diamonds ↩︎
- Naturaldiamonds.com, Isha Ambani just wore the most expensive red-carpet jewel of all time ↩︎
- The GIA, GIA diamond cut grade: six things you need to know ↩︎
- Diamonds.pro, Diamond resale value ↩︎
- Diamonds.pro, Diamond ring appraisals: everything you need to know ↩︎
