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Short answer: A cut diamond has five main parts: the table (the large flat top facet), the crown (the upper section above the widest point), the girdle (the thin widest edge), the pavilion (the lower cone that reflects light back up) and the culet (the tiny point or facet at the bottom). A standard round brilliant has 57 or 58 facets. The angles and proportions between these parts decide how much a diamond sparkles.
Knowing diamond anatomy helps you understand grading reports and choose a well-cut stone. When a report lists a 57% table, a 61.8% depth or a medium girdle, those numbers describe the parts in this guide. Once you know what each part does, the numbers stop being jargon and start telling you how the stone will look on your hand.
This guide explains every part of a diamond, how the facets are arranged, how proportions control sparkle, how the anatomy changes for fancy shapes, and where to find each measurement on a certificate. Everything here applies equally to lab grown diamonds, mined diamonds and moissanite, because all three are cut to the same basic design.
Parts of a Diamond
Picture a round diamond from the side. The top half is a low, wide cone with a flat top; the bottom half is a deeper cone that comes to a point. The thin edge where the two halves meet is the widest part of the stone.
| Part | Where it is | What it does |
|---|---|---|
| Table | Flat top facet | Main window for light to enter and exit |
| Crown | Upper angled section | Creates fire by splitting light into colors |
| Girdle | Widest outer edge | Protects the edge; where prongs grip |
| Pavilion | Lower cone | Reflects light back up through the top |
| Culet | Bottom point | Usually "none" (a point) in modern cuts |
| Diameter | Width across the girdle | Determines face-up size |
| Depth | Table to culet height | Affects light return and apparent size |
The table
The table is the largest single facet, the flat top you look straight into. It lets light in and is the main window through which brilliance comes back out. On a report it is shown as a percentage of the diameter. A table that is too large can reduce fire, while one that is too small can make the stone look darker in the center.
The crown
The crown is the sloping section between the table and the girdle. Its angled facets bend light as it leaves the stone and split it into flashes of colour, which jewelers call fire. A steeper crown angle generally means more fire; a very shallow crown gives a flatter, glassier look.
The girdle
The girdle is the narrow band around the widest point. It sets the stone's diameter, protects the edge from chipping and gives prongs or a bezel something to grip. It is also where a laser inscription, such as a report number, is usually placed.
The pavilion
The pavilion is the lower cone. Its facets act like mirrors: light that enters through the top bounces off them and returns through the table and crown. The pavilion angle is the single most important factor in brilliance.
The culet
The culet is the very bottom of the stone. Most modern diamonds end in a sharp point, listed as "none" on a report. Older cuts often had a small flat facet here to protect the tip, which can show as a tiny circle when you look down through the table.
Facets of a Round Brilliant
- Crown: 1 table, 8 star facets, 8 bezel (kite) facets, 16 upper girdle facets.
- Pavilion: 8 main pavilion facets and 16 lower girdle facets.
- Culet: sometimes a tiny extra facet, making 58.
That gives 33 facets on the crown and 24 on the pavilion, for 57 in total, or 58 with a faceted culet. The facets are arranged in a precise pattern of eights, which is why a well-cut round diamond shows a crisp, symmetrical pattern when you look into it. The girdle itself may also be faceted, but those small facets are not counted in the standard total.
Shown: Round Cut Moissanite Solitaire Stud Earrings With Classic Six Prong Setting
Brilliance, Fire and Scintillation
Every part of the diamond works toward three visual effects. Knowing the difference helps you describe what you like when you compare stones.
- Brilliance: the bright white light reflected back to your eye. It comes mainly from the pavilion reflecting light up through the table.
- Fire: the flashes of rainbow colour. They come from the crown facets bending and splitting light as it exits.
- Scintillation: the sparkle and pattern of light and dark that moves as you or the stone moves. It depends on the number, size and arrangement of facets.
Moissanite is cut with the same anatomy, but its higher refractive index (about 2.65, compared with about 2.42 for diamond) means it bends light more strongly. That is why moissanite tends to show more visible rainbow fire than a diamond of the same cut.
How Proportions Affect Sparkle
A diamond's parts only work when they are in balance. The goal is simple: light should enter through the top, bounce off the pavilion facets and return to your eye, rather than leaking out of the bottom or sides.
Too shallow
Light leaks out of the pavilion, creating a dull, glassy look called a "fisheye." The stone may look large face-up for its weight but lacks life.
Too deep
Light escapes through the sides, making the center look dark and the stone look smaller face-up. Extra weight is hidden in the pavilion, so you pay for carats you cannot see.
Ideal
Light reflects from the pavilion back through the table and crown, creating maximum brilliance and fire.
Commonly cited ranges for a round brilliant
No single set of numbers guarantees a beautiful stone, but well-cut rounds tend to fall within these broad ranges. Use them as a starting point, not a strict rule.
| Measurement | Typical well-cut range | What happens outside it |
|---|---|---|
| Table % | About 54% to 58% | Too large can mute fire; too small can look dark |
| Depth % | About 59% to 63% | Too shallow looks glassy; too deep looks small and dark |
| Crown angle | About 33° to 36° | Too low reduces fire |
| Pavilion angle | About 40.6° to 41° | Small changes strongly affect brilliance |
Tip: Look at the pavilion and crown angles together, not one number on its own. A slightly larger table can work well with a steeper crown, and the cut grade on the report already accounts for how the parts combine.
Girdle Thickness
Girdles range from extremely thin to extremely thick. Thin to slightly thick is ideal: very thin girdles can chip, and very thick girdles add hidden weight without adding face-up size.
| Girdle grade | What it means | Practical effect |
|---|---|---|
| Extremely thin or very thin | Knife-like edge | Higher risk of chipping during setting or wear |
| Thin to slightly thick | Balanced edge | Durable and efficient; the preferred range |
| Thick | Noticeably wide edge | Some hidden weight; usually still fine |
| Very thick or extremely thick | Heavy band of girdle | Adds weight without adding face-up size |
Girdle surfaces also vary. A girdle can be left slightly frosted (bruted), polished smooth, or cut with many small facets. All three are normal and none affects the grade on its own.
Polish and Symmetry: The Finishing Details
Proportions describe the size and angles of the parts. Polish and symmetry describe how precisely those parts were finished. Both appear on grading reports, usually with grades from Excellent down to Poor.
- Polish: the smoothness of each facet surface. Fine polish lines or small marks left by the polishing wheel can slightly blur light as it passes through. Excellent or Very Good polish is usually invisible to the eye.
- Symmetry: how exactly the facets line up and meet. Misaligned facets, an off-center table or culet, or a girdle that wavers can disturb the light pattern. Good symmetry is what gives a round diamond its crisp, even look.
For most shoppers, Excellent or Very Good polish and symmetry are a sensible target. Below that, the effects can start to show as uneven sparkle, especially in larger stones where every facet is easier to see.
How to Check a Diamond's Anatomy Yourself
You do not need lab equipment to get a feel for how well a stone is cut. Whether you are looking at a stone in person, in photos or on a video call, try these checks:
- Look face-up first: a well-cut stone looks bright across the whole surface, without a dull center or a grey ring near the edge.
- Look for the pattern: in a round brilliant, you should see an even, symmetrical pattern of light and dark facets. Uneven patches can point to poor symmetry or angles.
- Check the side view: the crown should not look flat, and the pavilion should not look overly deep or bulging.
- Find the culet: with a loupe, a modern stone should show a sharp point centered under the table. An off-center culet suggests symmetry issues.
- Inspect the girdle: look for nicks or chips, especially on thin girdles and at the points of fancy shapes.
- Compare in different lighting: bright daylight shows brilliance, while spotlights show fire and scintillation.
Then compare what you see with the report. If the numbers look good and the stone looks lively, you have a well-cut diamond.
Shop the styles in this guide
How Anatomy Changes for Fancy Shapes
Every faceted diamond has a table, crown, girdle and pavilion, but the facet layout changes with the shape.
- Brilliant cuts: oval, pear, marquise, heart, cushion, radiant and princess cuts use triangular and kite-shaped facets similar to a round, designed for maximum sparkle.
- Step cuts: emerald and Asscher cuts have long, rectangular facets arranged in rows like steps. They show broad flashes of light and a "hall of mirrors" look rather than pinpoint sparkle, and they reveal clarity more easily.
- Keel line: elongated shapes such as oval, marquise and emerald cuts end in a line along the bottom of the pavilion rather than a single point.
- Bow tie: ovals, pears and marquise cuts can show a darker bow-tie shape across the center, caused by the pavilion facets in that area not returning as much light. A well-cut stone keeps it subtle.
- Points: pear, marquise, heart and princess cuts have sharp points at the girdle, which are best protected by V-prongs or a bezel.
| Cut style | Facet shape | Visual effect |
|---|---|---|
| Brilliant (round, oval, pear) | Triangles and kites | Bright, lively sparkle and fire |
| Modified brilliant (cushion, radiant) | Mixed brilliant patterns | Sparkle with a softer or crushed-ice look |
| Step cut (emerald, Asscher) | Long rectangles in rows | Broad flashes and a clean, mirror-like look |
If you love the anatomy of a particular shape, browse our lab diamond round, lab diamond oval and lab diamond emerald collections to see how each one looks set in a ring.
How the Anatomy Affects Setting Choice
The parts of a diamond also guide how it should be set:
- Girdle: prongs and bezels grip the stone here, so a very thin girdle needs a careful setter.
- Pavilion depth: a deeper stone needs a taller setting, which raises it higher off the finger.
- Points and corners: fragile tips on pear, marquise and princess cuts should sit under a protective prong.
- Culet: a pointed culet must not touch the band or basket, so the head is built with room beneath it.
Our setters check each stone's proportions before choosing the head, so the diamond sits securely and shows as much light as possible.
Where to Find This on a Certificate
Grading reports list table %, depth %, crown angle, pavilion angle, girdle thickness and culet. Learn more in IGI vs GIA certificates.
Both IGI and GIA grade lab grown diamonds. Their reports typically include a proportions diagram, a side-view drawing of the stone labelled with each measurement from this guide. For round diamonds the report also gives an overall cut grade, which combines the proportions with polish and symmetry. If you see a laser inscription listed, it is written on the girdle and matches the report number, so you can confirm the stone and the report belong together.
Well-Cut Stones at Ivevar
We select well-proportioned lab grown diamonds and moissanite and hand-set them in our Surat workshop. Many of our lab grown diamonds come with IGI certificates, and every piece ships worldwide with free shipping and 30-day easy returns (pierced earrings are returnable only if faulty). Browse stud earrings, explore lab grown engagement rings, or book a virtual appointment to look at stones with our team.
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Frequently Asked Questions
How many facets does a round diamond have?
57, or 58 if the culet is faceted.
What is the table of a diamond?
The large flat facet on top. It is the main window through which light enters and leaves the stone.
What does the pavilion do?
It reflects light back up to create brilliance. The pavilion angle has more effect on how bright a round diamond looks than any other single measurement.
What is a culet?
The bottom point; most modern cuts have none (a point). A large, flat culet on an older stone can show as a small dark circle in the center when viewed face-up.
Why does girdle thickness matter?
Very thin girdles can chip; very thick ones add hidden weight. Thin to slightly thick is the safe middle ground.
What is the bow tie in an oval diamond?
A darker, bow-tie-shaped area across the center of some ovals, pears and marquise cuts. It comes from how the pavilion facets return light, and a well-cut stone keeps it light and subtle.
Do lab grown diamonds have the same anatomy as mined diamonds?
Yes. Lab grown diamonds are chemically, physically and optically the same as mined diamonds, and they are cut to the same proportions and facet patterns.
Is moissanite cut the same way as diamond?
Moissanite uses the same parts and facet layouts, so a round moissanite also has a table, crown, girdle, pavilion and culet. Its higher refractive index gives it more visible rainbow fire.
What is more important, table size or depth?
Neither on its own. Sparkle depends on how all the proportions work together, which is why the overall cut grade is the best single guide.
The Bottom Line
Table, crown, girdle, pavilion and culet work together to create sparkle. Good proportions matter more than any single number, so read the cut grade first, then use the measurements to compare stones you already like.
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Author Bio
Aumsri Pradhan
Founder, Ivevar Luxury
Aumsri Pradhan is the founder of Ivevar Luxury, a Surat-based fine jewelry brand that designs and handcrafts lab grown diamond and moissanite jewelry in its own workshop. She leads the brand's design and customer experience, from engagement rings and bridal sets to custom pieces made to each client's story. Through the Ivevar blog, she shares practical guidance on lab grown diamonds, moissanite, diamond grading and ring design to help buyers choose with confidence.
