What is diamond cutting, exactly? In short, it’s the craft that turns raw, opaque crystallized carbon into the luxury diamonds worn on ring fingers and red carpets the world over. But it’s also much more than a technical process. Diamond cutting is where geology meets artistry, where centuries of craft tradition meet laser-guided precision and where every decision made by a cutter shapes not just a gem’s beauty, but its value.
The stakes of that craft have never been clearer than in 1908, when diamantaire Joseph Asscher was entrusted with cutting the 3,106-carat Cullinan diamond, the largest gem-quality rough diamond ever found. After months of painstaking analysis, he made the first cut by hand with a single blow. The result was nine major diamonds and 97 smaller ones, many of which now sit in the British Crown Jewels. Asscher also gave his name to one of the most enduring cuts in history1.
That story captures something essential about diamond cutting: the decisions made in those early moments of contact with the rough stone reverberate for centuries. Cut quality shapes how a natural diamond interacts with light, determining its fire (those flashes of spectral color), its brilliance (white sparkle) and its scintillation (the play of light as the gem moves)2. A well-executed cut transforms a rough diamond into something that commands attention. A poor one permanently diminishes a gem that nature spent billions of years creating. The impact on diamond value is direct and lasting.
The history of diamond cutting
The history of diamond cutting is really one of expanding human ambition. Early diamonds were worn in their natural octahedral crystal form, prized more as talismans than gemstones. The first deliberate cutting emerged in India, where craftspeople began polishing diamond surfaces to enhance their natural luster3.
Medieval European gem cutters developed the point cut in the 13th century by smoothing the apex of the natural crystal form. The table cut followed, slicing the top of the crystal to create a flat surface and, with it, the first real engagement with light management. By the 15th and 16th centuries, the rose cut had emerged: a flat-bottomed gem with a domed top covered in triangular facets, popular throughout the Renaissance and still beloved in vintage jewelry today4.
The 17th and 18th centuries brought more refined tools and a growing understanding of geometry. The old mine cut and the old European cut appeared, rounder and more faceted than their predecessors, releasing considerably more brilliance. Then in 1919, a Belgian-American engineer named Marcel Tolkowsky published a mathematical thesis that would change everything. His ideal proportions for the round brilliant cut, calculated to maximize light return and optical performance, formed the basis of the modern brilliant cut still dominant today5. The history of diamond cutting is, in many ways, a centuries-long pursuit of the perfect angle.
The diamond cutting process
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 optimize 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 diamond cutting equipment. This method has been widely replaced by machine-led diamond cutting, which involves advanced lasers and scanning systems.
Cleaving and sawing
Once the plan is set, the rough is divided. Cleaving splits the diamond along its natural crystalline planes using a blade and mallet, a technique requiring precise knowledge of the stone’s internal grain. Get it right and the rough divides cleanly. Get it wrong and the stone shatters6.
Sawing, by contrast, cuts across the grain. Traditional sawing uses phosphor bronze blades coated with diamond dust, rotating at speed to make controlled cuts. Today, laser sawing has largely replaced blade sawing in modern facilities: it’s faster, generates less heat and can follow the precise paths mapped in 3D software with sub-millimeter accuracy7.
Girdling and bruting
Girdling establishes the diamond’s outline, rounding it into the desired silhouette before faceting begins. The traditional method, bruting, involves rotating two diamonds against each other to grind down the edges. Modern mechanical bruting wheels offer greater consistency and control, particularly for high-volume production, though hand bruting is still used for complex or irregular shapes8.
Symmetry at this stage is everything. An uneven girdle carries its imperfection forward through every subsequent step, quietly undermining the diamond’s light performance no matter how skilled the faceting that follows 9.
Faceting diamonds
Faceting is where the diamond’s optical character takes shape. Crown facets sit above the girdle and govern how light enters the gem; pavilion facets sit below and determine whether that light reflects back to the viewer or leaks out the sides. The geometry has to be exact10.
Two broad approaches define the field. Brilliant cuts use triangular and kite-shaped facets radiating from the center, engineered to maximize sparkle and light return. Step cuts use parallel rectangular facets arranged in tiers, producing a mirror-like, architectural effect that prizes clarity and restraint over brilliance11. Each has its devotees and each makes entirely different demands of the rough diamond and the cutter working it.
Polishing the diamond cut
Polishing is the final act, and the one that separates a diamond that dazzles from one that merely glints. Rotating wheels embedded with diamond dust (the only material capable of working a diamond’s surface) refine each facet to a flawless mirror finish. Hand polishing allows the cutter to adjust in real time while machine polishing delivers consistency at volume12.
A poorly polished facet introduces microscopic surface irregularities that scatter light before it reaches the eye13. The difference isn’t always visible in a grading report. It’s always visible in person.
Grading diamond cut and symmetry
After polishing, the GIA evaluates cut quality against its five-point scale: Excellent, Very Good, Good, Fair, and Poor. The grade reflects a combined assessment of proportions (table size, crown angle, pavilion depth), symmetry (how precisely facets align and mirror each other) and polish (surface quality across every facet).
An Excellent grade means all three elements are working in concert to maximize light return. But a diamond can carry an Excellent overall grade while showing Very Good symmetry and that gap matters in practice: subtle asymmetries affect how a gem reads in motion, even if they don’t register in a static report. The full proportions breakdown always tells a more complete picture than the headline grade alone14.
Certification explained
A diamond grading certificate is the definitive record of a diamond’s qualities: cut grade, clarity, color, carat weight and precise proportions. The three principal certification bodies are the Gemological Institute of America (GIA), the International Gemological Institute (IGI) and the American Gem Society (AGS). GIA is widely regarded as the gold standard and its grading methodology is the most rigorous and consistent in the industry.
ADIF tip: For buyers, a certificate is both documentation and assurance. For resellers and insurers, it’s the foundation of valuation. A diamond without one is a diamond whose qualities you’re taking entirely on faith.
Hand-cut vs machine-cut diamonds
Hand cutting is the haute couture of diamond crafting. A skilled diamantaire works with cutting wheels, loupes, saws and hand-held faceting arms, making every decision in real time, guided by experience and instinct built over years at the wheel. Each gem is treated as a singular project, assessed and shaped entirely on its own terms.
Machine cutting brings a different kind of mastery: lasers, 3D scanners and CAD software executing cuts with automated precision that no human hand can consistently replicate. Skilled operators and planners remain essential throughout, setting parameters and inspecting results, but the physical execution belongs to the technology. Both methods are used in the diamond manufacturing process and sometimes combined within a single gem’s journey from rough to finished diamond.
Hand-cut diamonds
A hand-cut diamond, sometimes called an “old cut” diamond, carries something that no algorithm can replicate: the mark of a specific person’s judgment. Every inclusion, every quirk of the crystal structure, every unexpected turn in the rough is something a skilled cutter encounters directly and responds to in the moment. That responsiveness is a craft in itself.
The result is a diamond with genuine individuality. Collectors and connoisseurs seek out hand-cut diamonds precisely because they bear the evidence of the decisions made to shape them, the small asymmetries and distinct character that distinguish them from the uniformity of machine production. Some of today’s finest hand-cut experts also incorporate 3D scanning technology in the planning phase, bringing old-world craft and contemporary analysis together before making the first cut15.
Machine-cut diamonds
Machine-cut diamonds are the product of extraordinary precision. Laser systems follow pre-mapped paths with tolerances measured in fractions of a millimeter; automated polishing machines deliver consistent results across large volumes. Speed, scalability and waste minimization are the defining advantages, with pre-mapped formulas designed to maximize carat retention from every rough.
Consistency is a genuine strength. Machine-cut diamonds typically achieve highly symmetrical proportions with minimal variation, which translates to reliable, predictable light performance at scale. And the quality ceiling is high: a well-executed machine-cut diamond is fully capable of achieving Excellent grades across every parameter. Both methods align with the GIA’s 4Cs of diamonds grading framework. Execution, not method, determines the result.
Choosing between hand-cut or machine-cut diamonds
Knowing what’s involved, it’s 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 deliver something equally valuable in different terms: the confidence of consistency. Their proportions are more uniform, their symmetry more predictable, and for buyers prioritizing technical precision and reliable light performance across a range of options, that’s a compelling case. What some describe as minor irregularities in hand-cut diamonds, collectors often read as character.
Neither approach is inherently superior. The question is what a buyer is actually looking for: the singularity of artisan craft, or the refined exactness of precision technology. Both are capable of producing diamonds of outstanding beauty.
Types of diamond cuts and shapes you should know
When most people ask about diamond cuts, they’re often thinking about shape: the outline of the gem and the style of faceting that defines it. The two are related but distinct. Cut quality refers to how well a diamond is proportioned and finished; shape refers to its silhouette. Each shape has its own faceting approach, its own relationship with light and its own emotional meaning. The full range of diamond shapes is broader than most buyers realize. Here are the ones worth knowing:
Brilliant cut
The round brilliant cut is the gold standard of diamond cuts, designed by Marcel Tolkowsky in 1919 to extract maximum light return through 58 precisely angled facets. No other cut produces more fire and brilliance, which is why it accounts for the majority of engagement ring sales worldwide16. A smaller round brilliant, well cut, will routinely outshine a larger diamond in a less optimized shape.
Princess cut
Square or rectangular with sharp, uncut corners and a brilliant-cut facet arrangement, the princess cut delivers modern geometry and high sparkle in equal measure17. The second most popular engagement ring cut, it suits buyers who want the optical performance of a round brilliant in a more architectural silhouette.
Old mine cut
A predecessor to the modern brilliant, the old mine cut is a hand-cut, antique cushion shape with a high crown, small table and softly rounded edges. Developed in the 18th and 19th centuries under candlelight, it produces a slower, warmer sparkle that feels distinctly intimate, less engineered brilliance, more atmosphere. Taylor Swift’s 8–10 carat old mine cut diamond brings this historic cut into a modern spotlight, pairing vintage character with contemporary cultural relevance.
Emerald cut
With its long parallel facets, cropped corners and the cool restraint of a step cut, the emerald doesn’t compete with brilliant cuts on sparkle. Its open facets place clarity front and center, which is why truly high-clarity natural diamonds show to exceptional advantage here18.
Heart shape
This is a modified brilliant cut in a symmetrical heart form and one of the most demanding cuts to execute. Even slight asymmetry between the two lobes is immediately apparent to any observer19. The heart shape is often chosen for sentimental jewelry and anniversary pieces, where the symbolism of the shape is as much the point as the sparkle.
Asscher cut
A square step cut with deeply cropped corners and a concentric square pattern that gives it an almost hypnotic depth when viewed from above. Developed by Joseph Asscher in 190220, its geometric precision carries a distinctly Art Deco character. The cut has driven multiple revivals, most recently as part of the broader appetite for vintage and antique fine jewelry.
Cushion cut
The cushion reads as romantic rather than precise, which is why it has been a consistent engagement ring favorite across generations. It’s a square or rectangular shaped diamond with rounded corners and large facets that give it a soft, warm brilliance. Kim Kardashian’s 15-carat cushion-cut diamond21, one of the most photographed engagement rings of the 2010s, brought the cut significant renewed attention.
Radiant cut
A rectangular or square cut that borrows the clean lines of a step cut and applies a brilliant facet pattern to the interior. The result is a high-sparkle, versatile shape that handles color particularly well, making it a natural choice for fancy-colored natural diamonds where intensity and saturation are the focus22.
Oval cut
An elongated brilliant cut that plays an elegant optical trick: distributing its carat weight across a larger surface area, it appears bigger than a round diamond of identical weight23. The elongated shape also creates a flattering lengthening effect on the finger. Hailey Bieber’s 6-carat oval solitaire diamond engagement ring crystallized the cut’s cultural moment and demand has remained strong since.
Marquise cut
Elongated with pointed ends, the marquise maximizes perceived size relative to carat weight more aggressively than almost any other cut. It carries strong vintage associations and has returned to contemporary fine jewelry with real confidence, especially after Selena Gomez’s 2024 engagement. Buyers should be attentive to cut quality: a poorly executed marquise can develop a “bow-tie” shadow across its center, a dark zone where light fails to return, which even a certificate won’t always flag24.
Pear shape
A teardrop silhouette that combines elements of the round brilliant and the marquise into one of the most technically demanding shapes to cut well. The 69.42-carat Taylor-Burton Diamond, purchased by Richard Burton for Elizabeth Taylor in 1969, remains the definitive cultural reference. Symmetry along the central axis is everything, even slight misalignment reads as imbalance at any size25.
Cabochon
A smooth, polished dome with no facets whatsoever. The cabochon is more common in colored gemstones than in diamonds, but it appears in artistic and vintage jewelry pieces where surface luster and form take precedence over light performance. Its contrast with traditional faceted diamonds is exactly the point26.
Baguette
A long, narrow rectangular step cut with parallel facets and clean, unembellished lines. Almost always used as an accent stone, the baguette’s restraint makes it the ideal supporting player in channel and pavé settings, amplifying a center stone without competing with it.
Trillion cut
This is a triangular brilliant cut with a bold, contemporary geometry that functions best as an accent stone, where its angular form creates striking visual contrast. As a center stone, the pointed corners require a protective setting27. When it works, it’s genuinely arresting.
How are lab-grown diamonds cut?
LGDs are almost always machine-cut, a reflection of the economics that drive lab-grown production: high volume, controlled costs, and the kind of standardized consistency that machine cutting delivers naturally. Exceptions exist, typically bespoke or high-end designer commissions that call for a hand-cut LGD to achieve a vintage or antique aesthetic, but these are a small fraction of the market.
What machine cutting cannot supply is context. Understanding what is a lab grown diamond at a fundamental level makes this clear: the chemistry is the same, but the 3.5 billion years of natural diamond formation and the rarity and individual character that comes with it cannot be replicated in a laboratory. They are, in the most literal sense, irreplaceable.
The cut is a choice. The diamond is forever
Both handcrafted and machine-cut natural diamonds are capable of producing extraordinary results. The choice, ultimately, is about what a buyer values: the individuality of artisan craft, the precision of advanced technology, or something shaped by the Earth itself over timescales that dwarf human comprehension. For the emotional value of diamonds that no cutting machine has ever been able to manufacture, natural diamonds remain without peer.
FAQs
Yes, and it’s more widespread than most buyers suspect. In high-volume commercial cutting operations, carat retention frequently takes priority over optical performance. A cutter who leaves a diamond slightly thicker or shallower than ideal preserves more weight, which translates to a higher carat grade and a higher price by weight, at the direct expense of brilliance.
The signs are readable without specialist equipment: a flat, glassy quality under light, dark patches that don’t shift when the diamond moves, a stillness when the gem is rotated that a well-cut diamond would never have. Always request the GIA cut grade and examine the full proportions diagram before committing. The relationship between diamond carat and cut quality is one of the most important things any buyer can understand.
Cut and color are measuring entirely different things. Cut governs how a diamond performs with light: the brilliance, fire and scintillation produced by the geometry of its facets, proportions and symmetry. Color, for colorless to near-colorless diamonds, refers to the presence or absence of yellow or brown body tone, graded on the GIA’s D-to-Z scale.
The two interact in practice. A well-cut diamond draws the most from its color grade, maximizing the clarity and luminosity of the light passing through it. But they remain fundamentally distinct characteristics. The color of diamonds is a geological fact; cut quality is a human achievement.
Choosing a natural diamond for an engagement or wedding piece means choosing something genuinely singular, a gem formed over billions of years that will never be reproduced. Why are diamonds used for engagement rings? It runs deeper than convention: they connect the wearer to something ancient, rare and permanent in a way that no manufactured alternative can match.
Taylor Swift’s engagement ring from Travis Kelce features an old mine cut diamond. It’s a vintage cut developed in the late 17th and 18th centuries and the direct predecessor to the modern round brilliant.
The ring landed as a cultural statement as much as a jewelry choice. In a moment when fine jewelry collectors are increasingly drawn to provenance, character and craft over standardized perfection, an old mine cut reads as a deliberate position.
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