Ever wondered how a rough diamond becomes that lustrous gemstone in the jewellery store window? The answer lies in the process of cutting — an art form that India has excelled at for decades now (over ninety percent of the world’s diamonds are cut and polished here).1
Diamond cutting, whether done entirely by hand, by machine or a bit of both, is much more than just a technical skill; it’s a bona fide art form. And how successfully it’s done plays a huge part in a diamond’s value.
Just ask Joseph Asscher, the legendary diamantaire entrusted with cutting the 3,106-carat Cullinan diamond, the largest gem-quality rough diamond ever found2 (he’s also the man behind the famous Asscher cut).
After months of painstaking analysis, Asscher made the first cut by hand, using a single blow to cleave the huge gem in two. By the time Asscher had finished, there were nine major natural diamonds in total along with 97 smaller ones3, many of which now sit in the British Crown Jewels.
How the diamond cutting process works
The process of cutting a diamond is guided by a precise balance of science, artistry, and technical expertise. There are two methods of cutting diamonds and both aim to optimise light ‘return’ (how well a diamond reflects light) along with symmetry and carat weight, though both go about it very differently.
Handcrafted diamond cutting is carried out by highly trained experts who use visual inspection and manual tools. Previously the only way of cutting diamonds, this method has been widely replaced by machine-led diamond cutting, which involves advanced lasers and scanning systems.
Handcrafted diamond cuts vs machine precision cutting
Diamond cutting by hand is a traditional, manual process, where a skilled cutter uses tools like cutting wheels, loupes, saws and hand-held faceting arms. Each decision is made in real time, guided by artistry and experience, as well as a deep understanding of the diamond itself. In fact, because a diamond is the hardest natural material on Earth, only another diamond can cut or polish it — which is why polishing wheels are coated with fine diamond powder. Think of it as the haute couture of diamond crafting!
On the other hand, diamond cutting with machines uses high-tech equipment like lasers and scanners to perform automated tasks. Don’t be fooled into thinking computers do all the work, though — skilled operators and planners work alongside the machines, deciding on the cuts to be carried out and inspecting each diamond afterwards.
Both are used in today’s diamond manufacturing processes and sometimes even combined. However, luxury maisons’ preferences lean heavily towards hand-finished diamonds. Nonetheless, both handcrafted natural diamonds and those perfected by machines have their benefits and are highly respected.
What defines a hand-cut natural diamond?
There’s something undeniably special about a handcrafted diamond (or ‘old cut’ diamond, as they’re sometimes known). Think Mary-Kate Olsen’s Old European-cut engagement ring, or the centuries-old polki craftsmanship that continues to shine in Indian bridal jewellery and on Bollywood’s leading women.
A vast amount of time and effort is dedicated to shaping diamonds, using human intuition and personal touch. Cutters thoughtfully assess each rough diamond individually, taking into consideration its individual characteristics like inclusions, natural shape and potential carat yield in order to maximise beauty and brilliance. Using hand-held tools, they employ centuries-old diamond cutting techniques.
By doing it with their hands, cutters can easily react to what they learn about a diamond during the cutting process (like its crystal formation, or unexpected inclusions), which is why hand-cut diamonds are typically deemed to be of great quality and very precious. This is also why they, so often, turn into beloved family heirlooms that are passed down generations.
It’s important to note that some hand-cut diamond experts will employ the help of computer technology (like 3D scanners) to help them decide the best approach to diamond cutting before making any incisions.
How machine-cut diamonds achieve precision
Welcome to the age of algorithms and lasers! Machine-cut diamonds are shaped using advanced technology that brings speed and consistency4 to the cutting table.
Technologies such as 3D rough-diamond scanners, computer-aided design (CAD) software and laser systems allow cutters to analyse the rough gemstone and plan how best to shape it. Diamond cutting machines follow a pre-mapped model or formula that maximises carat retention, ideal for cost and carat savings5.
But these machines do not work independently. Skilled planners and operators determine how each diamond should be cut, programming the equipment and carefully monitoring every stage. Their goal is to balance precision with thoughtful use of the rough stone, ensuring the final result reflects both craftsmanship and efficiency.
A well-executed machine-cut diamond can achieve excellent grades for brilliance, polish and symmetry. Ultimately, the quality of a diamond depends less on the technology involved and more on the expertise guiding the process.
How to choose: Hand-cut or machine-cut diamonds?
Having some insight into the cutting process makes it easy to see why handcrafted diamonds carry an air of exclusivity and deep desirability. As well as heirloom pieces, their individuality makes them the go-to choice for people who really appreciate the expert craftsmanship behind a gemstone.
Machine-cut diamonds are more common where precision and efficiency are paramount. They’re usually perfectly symmetrical, with more consistent angles and proportions compared to hand-cut varieties — although those often add a little extra personality to the diamond’s individual character!
Quick tip: always keep the 4Cs of diamonds in mind because understanding the importance of a diamond cut could prove crucial when you’re shopping for a diamond.
How are lab-grown stones cut vs natural diamonds?
It’s a good question, especially with laboratory-grown stones (LGDs) becoming more common in the market6.
LGDs are almost always machine-cut. Due to the typical mass volume production, this helps ensure speed to handle the large batches and keeps costs low. However, there are rare cases, for a bespoke or high-end designer piece, when an LGD may be hand-cut to mimic an antique or vintage style.
If the heritage, sentimentality and personal backstory of a diamond appeals to you, it goes without saying that natural diamonds are your top choice. Truly individual, rare and unique compared to their lab-grown counterparts, natural diamonds tell a story of authenticity and legacy that LGDs just can’t replicate. With the oldest diamonds dating to around 3.5 billion years old, they’re filled with history and geological resonance.
Both handcrafted techniques and advanced technologies play a role in bringing a natural diamond’s brilliance to life. Behind every finished stone lies a careful balance of expertise, precision and time, all working together to reveal the diamond’s natural beauty.
For the wearer, however, the magic of a diamond is rarely about the cutting process itself. What matters is the finished diamond: how it looks, how it feels, and the moments it comes to represent.
Sources:
- Naturaldiamonds.com, Diamonds Are Cutting a Path Through India’s Water Crisis ↩︎
- Royalasscher.com, The Cullinan ↩︎
- Rct.uk, The Cullinan diamond ↩︎
- Carlsbadjewelrystore.com, The latest advances in diamond cutting technology ↩︎
- Stpl.com, Diamond sawing technology ↩︎
- Mckinsey.com, The diamond industry is at an inflection point ↩︎
