Diamond shapes
Ten shapes, what each one does with light, and what to check before you choose.
Shape is the first decision
Shape changes price, apparent size and how the stone behaves in light, and it is the hardest thing to change your mind about later, because the setting has to be made to hold it. Most people know which shape they want before anything else.
Two terms are worth having. A brilliant cut is faceted to return light as sparkle. A step cut has long parallel facets that give broad flashes and a clear view into the stone. Neither is better. They look different, and the difference is obvious in the videos.
Length-to-width ratio is the second number to know. It is the outline's proportion, and on elongated shapes it decides whether a stone reads slim or stubby. We print it on every product page, and the ranges below are the ones most buyers settle on. They are preferences, not rules.
Available now
Round
Brilliant cut · ratio 1.00
Fifty-seven facets arranged to return the most light of any shape. The only shape laboratories give an overall cut grade, so it is the easiest to compare stone against stone. It is also the most expensive per carat, because more rough is lost in cutting.
See 1 round diamondOval
Brilliant cut · ratio 1.30 – 1.50
A round stretched along one axis. It covers more of the finger than a round of the same weight, which is why it reads larger. Check the video for a bow-tie: a dark band across the centre, present to some degree in most ovals and distracting in a few.
See 1 oval diamondEmerald
Step cut · ratio 1.30 – 1.50
Long parallel facets and a large open table. Instead of sparkle it gives broad flashes and a clear view into the stone. That openness shows inclusions sooner, so clarity matters more here than in a brilliant cut.
See 1 emerald diamondPear
Brilliant cut · ratio 1.45 – 1.75
A brilliant with one rounded end and one point. Worn with the point toward the fingernail it lengthens the finger. Symmetry is the thing to check: the shoulders should match and the point should sit on the centre line.
See 1 pear diamondPrincess
Brilliant cut · ratio 1.00 – 1.05
A square brilliant with sharp, uncovered corners. It keeps more of the original rough than a round, so it costs less per carat. Those corners are the most vulnerable part of the stone and want a setting that protects them.
See 1 princess diamondNot in stock today
Our settings take these shapes, and we have none in the catalogue at the moment. Stock changes, so it is worth asking if one of them is what you want.
Cushion
Brilliant cut · ratio 1.00 – 1.20
A square or slightly rectangular outline with rounded corners. Facet patterns vary a good deal between cutters, so two cushions can look quite different. Judge by the video rather than the name.
None in the catalogue today.
Radiant
Mixed cut · ratio 1.00 – 1.35
A rectangular outline with trimmed corners and brilliant faceting inside. It behaves like a brilliant while holding a step cut's silhouette, and it hides inclusions better than an emerald cut of the same grade.
None in the catalogue today.
Marquise
Brilliant cut · ratio 1.85 – 2.10
A long boat shape with points at both ends. It has the largest face-up area per carat of any shape we cut. Both points are fragile, and a bow-tie is common, so watch the video closely.
None in the catalogue today.
Asscher
Step cut · ratio 1.00 – 1.05
A square step cut with cropped corners and deeply cut facets that draw the eye into the stone. Like the emerald cut, it rewards a higher clarity grade.
None in the catalogue today.
Heart
Brilliant cut · ratio 0.95 – 1.10
A brilliant with a cleft at the top. Everything rests on symmetry: the two lobes should match and the cleft should be distinct. Below about 0.50ct the outline becomes hard to read once the stone is set.
None in the catalogue today.
What to check on any shape
- Watch the video before the grades. A certificate cannot tell you whether a stone looks right to you.
- Look for a bow-tie on oval, pear and marquise: a dark band across the waist, caused by the cut shadowing the centre. Slight is normal. Heavy is worth avoiding.
- Check symmetry on pear, heart and marquise, where the eye finds an uneven outline quickly.
- Read the millimetres, not the carat, when comparing apparent size across shapes.
- Match the shape to the setting. Every setting lists the shapes it takes, and the configurator will not let you build a pairing that cannot be made.
Filter the listing by shape, or start from a setting and see which stones fit it.