A custom diamond shape is an outline cut to a brief rather than chosen from a standard list. The cutter plans the silhouette first, then arranges the facets inside it, so the finished stone is designed around one commission rather than adapted from a template.
A pear, marquise or cushion has recognised proportions. A custom shape sits outside those outlines and may be geometric, asymmetric or freeform.
What is a custom diamond shape and how is it defined?
Shape is the outline seen from above. Cut is the arrangement of facets and the proportions that decide how light moves through the stone.
The same silhouette can carry brilliant or step-cut facets and look quite different. A custom commission settles the outline and facet layout together, including proportions, corner treatment and depth.
How are custom diamond shapes created?
The cutter maps the rough crystal's geometry, inclusions and weight before setting the outline, because each shape decision affects yield.
- Planning. The rough is scanned and modelled to test possible outlines and predict how much weight each keeps.
- Cleaving or sawing. The crystal is divided along its natural grain into usable sections.
- Bruting. The stone is shaped towards its outline, now often by laser or computer-controlled shaping rather than by grinding a second diamond against it.
- Faceting. The facet pattern is cut in stages, blocking in the main facets and then the brilliant facets that create sparkle.
- Polishing. Each facet is polished and the stone is checked for symmetry, proportions and light behaviour before grading.
A silhouette that ignores the crystal's symmetry usually sacrifices more material. Natural rough tends to form as octahedra, HPHT lab-grown rough as cuboctahedra, and CVD as flat plates, so each form suits different outlines economically.
Which custom diamond shapes are available?
Most commissions adapt a recognised shape: stretching an oval, softening a cushion's corners or squaring an emerald cut.
| Shape | Visual effect | Character |
|---|---|---|
| Round brilliant | Bright, even light return with small, sharp flashes | The classic reference point |
| Princess (square) | Sharp corners, lively sparkle | Modern and architectural |
| Cushion | Soft corners, broad flashes | Romantic and vintage-leaning |
| Emerald | Long open facets, mirror-like steps | Calm and architectural |
| Pear | Teardrop with a single point | Distinctive and graceful |
| Marquise | Points at both ends, narrow body | Dramatic and elongating |
| Heart | Rounded lobes with a point | Sentimental and expressive |
| Custom geometric | Straight edges, deliberate symmetry | Contemporary and personal |
| Irregular freeform | Organic outline, asymmetric balance | Individual by design |
The facet layout matters as much as the outline. On a custom stone it is designed around your silhouette, which makes the result personal.
How to choose a custom diamond shape
- Start with the wearer's taste and existing jewellery rather than a trend.
- Elongated outlines can lengthen the appearance of the finger; wider shapes can balance a longer hand.
- Pointed outlines need protective claws at their tips, while bezels suit smooth outlines.
- Agree the budget early. Cut, yield and demand all affect what is possible.
- Decide whether the shape should reference a place, initial or personal idea.
Custom shapes in lab-grown and natural diamonds
Both origins can be cut into many outlines. The starting crystal affects how efficiently the cutter can work.
| Factor | Natural diamond | Lab-grown (HPHT) | Lab-grown (CVD) |
|---|---|---|---|
| Rough crystal form | Octahedral | Cuboctahedron | Flat tabular plate |
| Outlines the rough tends to suit | Round, pear, marquise | Cushion, princess, radiant | Emerald, princess, radiant |
| Range of custom outlines | Any outline the rough allows | Any outline the rough allows | Any outline the rough allows |
| Yield on fancy shapes | Moderate to high | Moderate | Often higher for flat outlines |
| Origin note | Natural diamonds are sourced in line with the Kimberley Process | No mining origin | No mining origin |
CVD crystals grow as flat plates, which can make rectangular outlines efficient to cut.
We source both origins with GIA or IGI certification for the centre stone. Natural diamonds are sourced in line with the Kimberley Process; that process applies to natural rough diamonds, not lab-grown stones.
A shape that belongs to one commission
A reference photograph is a useful starting point. We can also adjust the silhouette and proportions to create the line and character you want.
Symmetry and proportions still matter: a custom outline needs a sound facet plan to look lively.
If you would like to take this further, you can design a bespoke engagement ring with us from the first conversation through to the finished piece, read the diamond shapes guide for how the ten standard outlines behave, or contact À Vie Diamonds to talk through a shape you have in mind.
Frequently asked questions
What is the difference between diamond shape and diamond cut?
Shape is the outline of the stone seen from above, such as round, pear or marquise. Cut is the arrangement of facets inside that outline, along with the proportions that decide how much light returns to the eye.
Can a diamond be cut into a custom shape?
Yes, provided the rough is large enough and clean enough for the outline you want. The cutter's skill and the crystal's geometry affect how much material is lost, but they do not limit which outlines are possible.
Do custom shapes cost more than standard cuts?
Usually, yes. A complex outline takes more skilled bench time and tends to waste more of the rough, and that shows up in the price rather than in the certificate. Lab-grown rough can make some larger or more unusual outlines more affordable.
Which diamond shape suits an engagement ring?
It depends on the wearer's taste, the hand it will sit on and the setting you have in mind. Elongated shapes tend to lengthen the finger, while wider shapes balance a longer hand, so trying outlines against the hand is worth the effort.
Do lab-grown diamonds limit the shapes available?
No. Lab-grown and natural stones can both be cut to any outline the rough allows. The difference is in cutting efficiency, since CVD material grows as a flat plate and suits step cuts and rectangular outlines particularly well.
Last reviewed: November 2026, À Vie Diamonds