The bow-tie
A darker band across the middle of oval, pear and marquise stones, where light leaks rather than returns. A strong bow-tie dulls the stone; a faint one is normal. We choose stones where it is barely there.
The Shapes Guide
Every cut, and what it does.
Shape is the first thing anyone notices, and the most personal choice you will make. Here are the twelve shapes we cut and set, how each handles light, size and wear, and how to find the one that feels like you.
Shape, by the numbers
12shapes, cut and set by us
57facets on a round brilliant
54%longer: a one-carat marquise beside a round
Every shape held to the same standard. Meet the twelve
01 · Two families
Brilliant or step
Every shape belongs to one of two cutting traditions. Brilliant cuts are faceted like a star, to break light into sparkle. Step cuts have long, parallel facets, like a staircase, that return it in broad, calm flashes. Draw the line across the stone to see both.
BrilliantSparkle
StepFlash
BrilliantRound, oval, cushion, princess, radiant, pear, marquise, heart and trillion.
StepEmerald, asscher and baguette.
02 · The atlas
Twelve shapes, twelve characters
Choose a shape to read about it: how it looks, what it suits, and what to look for.
Brilliant cut · 57 or 58 facets
Round
The most brilliant of all shapes. Its facets are placed at angles refined over a century to return as much light as possible, and it suits every setting ever made.
- Ideal length to width
- 1.00
- Lovely in
- Solitaires, halos, studs and eternity bands
- Worth knowing
- Hides colour and inclusions better than any other shape.
- A little history
- Its modern proportions were set out by the mathematician Marcel Tolkowsky in 1919.
Brilliant cut
Oval
A round brilliant, gently stretched. It lengthens the finger and looks a little larger than a round of the same weight, with nearly all of its sparkle.
- Ideal length to width
- 1.35 – 1.50
- Lovely in
- Solitaires, halos and toi et moi rings
- Worth knowing
- Look for little or no bow-tie, the darker band some elongated stones show across the centre.
- A little history
- A modern classic, refined through the twentieth century and now one of the most loved engagement shapes.
Brilliant cut · softened square
Cushion
Rounded corners and broad facets give large, slow flashes of fire, with a soft, romantic character.
- Ideal length to width
- 1.00 – 1.10
- Lovely in
- Halos, vintage settings and three-stone rings
- Worth knowing
- Cushions vary more than any other shape from stone to stone. See them side by side.
- A little history
- Descended from the old mine cut, the favourite diamond shape of the nineteenth century.
Brilliant cut · square
Princess
Crisp, square and graphic: the most popular square shape, with a lively, modern sparkle.
- Ideal length to width
- 1.00 – 1.05
- Lovely in
- Solitaires, channel-set bands and studs
- Worth knowing
- Its pointed corners are its weak point, so they should sit under protective claws.
- A little history
- Introduced around 1980, it quickly became the square shape of choice.
Brilliant cut · cropped corners
Radiant
The brilliance of a round in the outline of an emerald, with a vivid, crushed-ice sparkle.
- Ideal length to width
- 1.00 – 1.35
- Lovely in
- Solitaires, three-stone rings and halos
- Worth knowing
- Its cropped corners make it robust enough for every day.
- A little history
- Created by the cutter Henry Grossbard in 1977.
Brilliant cut · teardrop
Pear
Half round, half marquise: a teardrop that slims the hand, as graceful in a pendant as it is in a ring.
- Ideal length to width
- 1.45 – 1.75
- Lovely in
- Pendants, drop earrings, solitaires and toi et moi
- Worth knowing
- Worn point towards the fingertip, it lengthens the hand. Look for evenly rounded shoulders.
- A little history
- Credited to the Flemish cutter Lodewyk van Berquem in the fifteenth century.
Brilliant cut · navette
Marquise
Long and pointed at both ends, it has the largest face-up area of any shape for its weight. Dramatic and regal.
- Ideal length to width
- 1.85 – 2.10
- Lovely in
- Solitaires, east-west rings and clusters
- Worth knowing
- Both points should be protected by V-shaped claws.
- A little history
- Said to be named after the Marquise de Pompadour, at the court of Louis XV.
Brilliant cut
Heart
The most romantic shape, and one of the hardest to cut well: the two lobes must match, and the cleft between them must be crisp.
- Ideal length to width
- 0.90 – 1.10
- Lovely in
- Pendants, solitaires and studs
- Worth knowing
- Most striking from about half a carat, where the outline reads clearly once set.
- A little history
- Heart-shaped stones have been given as tokens of love at European courts for centuries.
Brilliant cut · triangle
Trillion
A triangle with gently curved sides: bold, modern, and full of sparkle for its size.
- Ideal length to width
- 1.00
- Lovely in
- Three-stone rings and statement solitaires
- Worth knowing
- Superb as side stones, framing a round or oval centre.
- A little history
- Developed and named in the 1960s.
Step cut
Emerald
Long, parallel facets give calm, broad flashes of light, like a hall of mirrors. Understated, architectural and endlessly elegant.
- Ideal length to width
- 1.30 – 1.50
- Lovely in
- Solitaires, three-stone rings with baguettes, east-west
- Worth knowing
- Its open table shows the inside clearly, so clarity matters more than with any other shape.
- A little history
- Developed to cut emeralds, and beloved through the Art Deco years.
Step cut · square
Asscher
A square step cut with deep, cropped corners that draws the eye into a windmill pattern at its heart.
- Ideal length to width
- 1.00 – 1.05
- Lovely in
- Solitaires, Art Deco settings and studs
- Worth knowing
- It is cut deep, so it looks a little smaller face up than other squares of the same weight.
- A little history
- First cut in Amsterdam in 1902 by Joseph Asscher.
Step cut · slim rectangle
Baguette
A slim rectangle of long step facets, most often set beside a centre stone or in elegant rows.
- Ideal length to width
- 2.00 and longer
- Lovely in
- Side stones, eternity bands and Art Deco designs
- Worth knowing
- Tapered baguettes frame a centre stone beautifully.
- A little history
- Its name is French for a long loaf. It rose to fame in the Art Deco 1920s.
03 · True size
The same carat, a different presence
Carat is a weight, not a size. Here are all twelve shapes at the same weight, drawn to scale against a millimetre rule. Choose a carat weight.
Typical face-up measurements, length by width, in millimetres. Every stone's proportions differ a little.
04 · What shape changes
More than an outline
Scroll to see the four things a shape decides.
I
Sparkle, or flash
Brilliant cuts, such as round, oval and pear, break light into many small, lively points of sparkle. Step cuts, such as emerald and asscher, return it in broad, calm flashes, and show more of the stone's interior.
II
Presence
Shape changes how large a stone looks. Long shapes, oval, pear and marquise, spread their weight across more of the finger, so they look larger than a round of the same carat.
III
Everyday wear
Points and sharp corners are a diamond's most exposed edges. Marquise, pear, princess and heart shapes need claws that guard them; round, oval, cushion and radiant are the easiest to wear every day.
IV
Style
A round reads as timeless, an emerald cut as architectural, a pear as romantic. The shape you choose sets the character of the whole piece, and the stones that suit it.
05 · What to look for
The details that set a stone apart
Two stones of the same shape and grade can look quite different. These are the things our gemmologists check for every shape.
The window
A pale, glassy area in the centre, where light passes straight through a stone cut too shallow. It shows most in step cuts. A well-cut stone has none.
Symmetry
Pear, heart and marquise shapes need two halves that mirror each other: even shoulders, a centred point, matching lobes. Small asymmetries are easy to see once set.
Corners and points
The corners of a princess and the points of a pear or marquise are where a diamond is most exposed. A setting with claws over every point keeps it safe for decades.
06 · For your hand
Finding your shape
There are no rules, only what makes you pause. But these are the starting points we suggest when clients ask.
What to considerShapes we would suggest
Shorter fingersLong shapes add length and slendernessOval, pear, marquise, elongated cushion
Long, slender fingersAlmost anything suits; wider shapes balance lengthRound, cushion, asscher, radiant
Wider handsA larger, longer stone keeps proportionOval, emerald, pear
Active, hands-on daysNo exposed points or sharp cornersRound, oval, cushion, radiant
The most sparkleBrilliant cuts return the most lightRound, oval, radiant, cushion
Quiet glamourStep cuts flash rather than sparkleEmerald, asscher, baguette
The largest look per caratLong outlines spread their weightMarquise, oval, pear
Try a few on. Most people know their shape the moment they see it on their own hand.
07 · History
Six centuries of shapes
Every shape was once an invention. A few of the moments that gave us the shapes we cut today.
1400s
The pear
The Flemish cutter Lodewyk van Berquem is credited with the pear shape and with polishing diamonds using a wheel and diamond dust.
1700s
The marquise
At the French court of Louis XV, the marquise shape is said to be named after the Marquise de Pompadour.
1800s
The old mine cut
Cut by hand to save weight, the softly square old mine cut is the ancestor of today's cushion.
1902
The Asscher
Joseph Asscher of Amsterdam creates the square step cut that bears his family's name.
1919
The ideal round
Marcel Tolkowsky publishes the proportions for a round brilliant that returns the most light, the basis of the modern round.
1920s
Art Deco
Step cuts, emeralds and slim baguettes define the geometric jewellery of the Art Deco years.
1977
The radiant
Henry Grossbard brings brilliant faceting to a rectangle with cropped corners.
1980
The princess
A square brilliant with crisp corners arrives, and soon becomes the most popular square shape.
Questions
Which shape sparkles the most?
The round brilliant. Its proportions are designed to return as much light as possible. Oval, cushion and radiant shapes come close.
Which shape looks the largest for its weight?
Long shapes: marquise first, then oval and pear. They spread their weight across more of the finger than a round of the same carat.
Which shapes are the most durable?
Shapes without points or sharp corners: round, oval, cushion and radiant. Pointed shapes are just as hard, but need claws that protect their tips.
What is a bow-tie?
A darker band across the middle of oval, pear and marquise diamonds. A faint one is normal; a strong one dulls the stone. We select stones where it is minimal.
Do fancy shapes cost less than rounds?
Often a little, per carat. Cutting a round brilliant sacrifices more of the rough crystal, so rounds usually carry a small premium.
Can a ring combine two shapes?
Yes. Toi et moi rings pair two stones, often a pear with an oval or round, and three-stone rings often frame a centre with trillions or baguettes.
Is every shape held to the same standard?
Yes. Every Diamos diamond, whatever its shape, meets the same colour, clarity and cut standard, and is certified by IGI.