Lab-Grown Diamond Shapes: A Complete Guide to Choosing the Right One

Shape is the most defining visual decision in a diamond. It sets the entire character of a ring. It determines how large the stone looks, how it sparkles, and how it sits on the hand. Before colour, before clarity, before carat, shape is the choice that catches the eye first.

Lab-grown diamonds come in the same shapes as natural diamonds. This gives Australian buyers more freedom than ever to choose based on beauty and personal style rather than budget constraints alone. This guide walks through every lab-grown diamond shape, explains what makes each one distinct, and offers practical guidance for choosing the right one.

Diamond Shape vs Cut: What's the Difference

Shape and cut are often used interchangeably, but they mean different things. Shape is the diamond's outline or silhouette. Round, oval, emerald, pear. It is the design choice, visible from across a room.

Cut refers to how skilfully the stone is faceted, proportioned, polished, and finished, and how well it returns light. A well-cut diamond, regardless of shape, will be bright and lively. A poorly cut one will appear dull, even with perfect colour and clarity.

The nuance is this: a formal cut grade is only assigned to round brilliants by the major gemological laboratories. Fancy shapes, which is the industry term for any shape that is not round, are judged on proportions, symmetry, and polish rather than receiving an overall cut grade.

The practical takeaway is simple. Choose the shape you love, but never compromise on cut quality within that shape. Cut is what brings any shape to life.

The Main Lab-Grown Diamond Shapes at a Glance

Lab-grown diamonds are cut into all the same shapes as natural diamonds. These shapes fall into two families.

Brilliant cuts include round, oval, princess, pear, marquise, radiant, heart, and cushion. These are faceted for maximum sparkle, with numerous triangular and kite-shaped facets designed to return light as brightness and fire.

Step cuts include emerald, Asscher, and baguette. These are faceted in clean, parallel rows, creating a clear, architectural look with broad flashes of light rather than the scattered sparkle of brilliant cuts. The result is elegant and understated, but less fiery.

This distinction matters because it affects sparkle, clarity needs, and how inclusions show. Step cuts reveal everything. Brilliant cuts hide small imperfections.

Beyond these established categories, the lab-grown diamond market has opened the door to greater experimentation. Unconventional shapes are beginning to emerge, driven by buyers seeking something distinct. The moval, a hybrid of marquise and oval, offers the elongated silhouette of a marquise with the softer curves of an oval. Step-cut pears and ovals combine the clean lines of step faceting with the familiar outlines of these popular shapes. Coffin cuts, with their striking geometric silhouette, appeal to those who want a piece that is unmistakably individual.

These shapes remain relatively rare, but their presence signals a broader shift. Lab-grown diamonds, free from the yield constraints of natural rough, allow cutters to explore forms that were previously impractical or uneconomical. For buyers who value individuality as much as tradition, these emerging shapes offer something genuinely new.

A Guide to Every Lab-Grown Diamond Shape

Round Brilliant

The classic and most popular shape worldwide. A round brilliant features 57 or 58 facets engineered for maximum brightness, fire, and sparkle. It suits timeless, universally flattering taste. This is the only shape that receives a formal cut grade from major laboratories, so prioritising an Excellent cut is essential. Round brilliants are also the most forgiving of slightly lower colour and clarity grades, as the intense sparkle masks inclusions. In the lab-grown market, round is the most in-demand and widely available shape, offering strong budget flexibility. It remains the most expensive shape per carat, but lab-grown pricing makes it far more accessible than its natural counterpart.

Oval

A brilliant-cut elongated shape with round-like sparkle and a flattering, finger-lengthening silhouette. Oval has become one of the most sought-after shapes in Australia. It suits those who want brilliance with a modern look that also appears larger per carat. When buying an oval, watch for the bow-tie effect, seek even ends, and prioritise good symmetry. Oval is a top seller in the lab-grown category, delivering a more visible size for the same carat weight.

Princess

A square, sometimes slightly rectangular, brilliant cut with sharp uncut corners and strong fire. The princess is the modern classic, suited to contemporary tastes that want sparkle without the round silhouette. The pointed corners can chip, so protective settings such as bezels or V-prongs are recommended. Princess cuts hide inclusions reasonably well and are efficient to cut, making them an excellent value in lab-grown diamonds.

Cushion

A square or rectangular shape with soft, rounded corners and large facets. The cushion has a romantic, vintage-leaning character with a warm, glowing light. The elongated cushion has surged in popularity in Australia. This shape suits those who love softness and antique character. The rounded corners wear well for daily life. Faceting varies significantly between cushions, so each stone should be evaluated visually. Lab-grown cushion cuts offer strong value, with the elongated form increasingly requested.

Emerald

A step cut. Rectangular with cut corners and long, parallel facets creating a hall of mirrors effect of broad flashes rather than scattered sparkle. The emerald shape is sophisticated, architectural, and quietly luxurious. It suits minimalists who prize elegance and clarity over fire. The open table reveals everything, so higher clarity and colour grades are essential. In the lab-grown market, emerald is a signature look for many jewellers, including LOHR, and lab-grown pricing makes the higher clarity this shape demands far more attainable.

Pear

A teardrop combining the round and marquise, with one rounded end and one pointed end. The pear shape is distinctive, elegant, and finger-flattering, with a large spread on the hand. It suits individuality and romance. When buying a pear, watch for the bow-tie effect, seek symmetry, and protect the point with the setting. Pear is economical relative to its visual size and is rising quickly in popularity for lab-grown diamonds.

Radiant

A brilliant-faceted shape with a rectangular or square outline and cropped corners. The radiant gives the silhouette of an emerald with the sparkle of a round. It suits those who want clean lines and serious brilliance. The cut corners wear well. Radiants come in both square and elongated versions, so specifying which is important. Elongated offers more finger coverage. This shape masks inclusions well and is a strong-value sparkler trending in modern Australian designs.

Asscher

A square step cut with cropped corners and a high crown. The Asscher is like a square emerald, with a deep hall of mirrors effect and Art Deco glamour. It suits lovers of vintage geometry and understated elegance. As a step cut, it demands higher clarity and colour because flaws and tint show clearly. The bevelled corners are durable. Efficient cutting yields excellent value in lab-grown diamonds, and the needed clarity is more affordable than in natural stones.

Marquise

An elongated boat shape with two pointed ends. The marquise offers the largest face-up surface area per carat, meaning it looks the biggest for its weight and elongates the finger. It suits the bold and the value-conscious. This shape is most prone to a visible bow-tie effect. Both points need protection in the setting. Symmetry between the two halves is critical. Marquise maximises perceived size for the budget, making it a strong choice in lab-grown diamonds.

Heart

A brilliant-cut shape with a cleft at the top and a point at the bottom. The heart is the romantic symbol, requiring superb symmetry so both halves mirror each other exactly. It suits the openly sentimental. Hearts need excellent symmetry, can show a bow-tie, and smaller hearts lose definition once set, so sizing up where possible is advisable. The heart is a distinctive, expressive choice and is widely available in lab-grown diamonds.

Baguette and Trillion

A baguette is a small, elongated step cut with clean lines and minimal sparkle. It is classic as a side stone or in three-stone rings. Trillion is a triangular brilliant cut, lively and contemporary, used as a centre stone or as side accents. Both shapes are fully available in lab-grown diamonds.

How Shape Affects Price and Value in Lab-Grown Diamonds

In natural diamonds, round brilliants cost the most per carat. Cutting a round wastes the most rough, and demand is highest. Fancy shapes, including emerald, princess, radiant, cushion, marquise, and pear, usually cost meaningfully less per carat. Elongated shapes also look larger for their weight.

The lab-grown market changes this equation. Because lab-grown rough is grown to purpose rather than mined, the price gaps between shapes are flatter. Overall prices are far lower across every category. Buyers can often afford a larger or higher-quality stone in any shape they choose.

The shape should be chosen for how it makes the wearer feel. Value is a welcome consequence of choosing lab-grown, not the primary driver.

Most Popular Lab-Grown Diamond Shapes and Australian Trends

Round brilliant remains the most popular shape overall, prized for unrivalled sparkle and timeless appeal. Australian commentary places roughly half the market.

Oval has surged to become the leading fancy shape in Australia. It has been repeatedly named the most requested cut for 2025 and 2026, loved for its modern, elongated look and finger-flattering silhouette.

Other rising shapes in the Australian market include elongated cushion, pear, radiant, emerald, and a marquise resurgence. Buyers are increasingly confident moving beyond round shapes to shapes that express individual style.

How Shape Interacts With the Other Cs and With the Setting

Shape does not operate alone. Clarity matters more for some shapes than others. Step cuts such as emerald and Asscher, along with any shape with a large open table, reveal inclusions and require higher clarity. Brilliant cuts hide them.

Colour shows differently by shape. Open shapes and step cuts display tint more readily. Brilliant cuts mask it effectively.

Carat is weight, not size. Shape determines how that weight reads on the hand. An elongated oval of one carat looks larger than a round of one carat. An Asscher of one carat looks smaller because its weight is carried in depth.

Setting and finger shape also matter. Elongated shapes lengthen and slim the finger. Pointed shapes such as marquise, pear, and princess benefit from protective settings. Halos amplify perceived size. Slim bands make a centre stone look larger.

Length-to-Width Ratio by Shape

Length-to-width ratio, calculated by dividing length by width, determines how elongated or compact a shape looks. It affects perceived size and finger flattery. Fancy shapes, which lack a standardised cut grade, ratio, and symmetry, are key comparison tools.

Ratio is ultimately a matter of personal preference. Two stones with the same ratio can still look different, so viewing the actual stone or high-quality imagery remains essential.

Which Lab-Grown Diamond Shape Looks the Biggest

Carat is weight, not visual size. Shapes that carry more mass across the top look larger face-up.

Ranked from largest-looking: marquise offers the greatest face-up area per carat, followed by pear and oval. Emerald and elongated radiant or cushion shapes also appear generous. Round, square princess, square cushion, and especially Asscher tend to look smaller per carat, as they carry weight in depth.

Because lab-grown diamonds allow buyers to stretch to larger carats affordably, choosing an elongated shape compounds the big look for the budget. Setting tricks such as halos and slim bands can further amplify perceived size.

The Bow-Tie Effect: What to Watch for in Elongated Shapes

The bow-tie effect is a dark, bow-tie-shaped shadow across the centre of elongated brilliant shapes. It appears most commonly in oval, marquise, and pear diamonds, and occasionally in elongated cushion and radiant cuts. The effect is caused by light leaking from the pavilion rather than reflecting back to the eye. It is a function of cut, not a flaw.

Almost every elongated brilliant has some bow-tie. A faint, soft shadow is normal. A harsh, black band across the centre signals a poor cut. Crucially, bow-tie is not stated on any grading certificate. It must be assessed visually, either by viewing the stone in person or through high-quality video.

Round, princess, emerald, and Asscher shapes do not show bow-ties.

How to Choose the Right Lab-Grown Diamond Shape

Four lenses help narrow the decision.

Personal style is the most important factor. Classic taste points to round. Modern taste suits a princess or a radiant woman. Vintage leanings favour emerald, Asscher, or cushion. Romantic sensibilities align with pear, marquise, or heart. The elegant all-rounder, suitable for almost anyone, is oval.

Hand and finger shape also matter. Elongated shapes lengthen shorter fingers. Petite hands suit round, oval, and cushion shapes, which do not overwhelm.

Lifestyle considerations matter for daily wear. Active wearers may prefer durable shapes without vulnerable points, such as round, cushion, or emerald, paired with protective settings.

Budget and priorities complete the picture. Round offers maximum sparkle. Elongated fancies offer maximum visual size for the carat weight. Step cuts offer clean, architectural lines. Lab-grown diamonds widen what is affordable across every category.

There is no single best shape. Only the shape that feels right for the wearer's story.

Are Lab-Grown Diamond Shapes the Same as Natural

Lab-grown diamonds are real diamonds. They are chemically, physically, and optically identical to mined diamonds. The only difference is the origin. One is formed underground over billions of years. The other is grown in a laboratory for weeks or months.

Because they are real diamonds, they are cut into the same shapes by the same processes. Two growth methods are used. HPHT, or High Pressure High Temperature, replicates the extreme conditions of the Earth's mantle. CVD, or Chemical Vapour Deposition, builds the crystal layer by layer from carbon-rich gas. Both methods produce gem-quality rough that can be cut into any shape.

Fancy shapes are fully available in lab-grown diamonds, often with excellent clarity, at a fraction of natural diamond prices. LOHR's diamonds are independently certified by IGI, ensuring each stone is graded to rigorous standards.

Common Myths About Lab-Grown Diamond Shapes

Cut and shape are the same thing. They are related but distinct. Shape is the outline. Cut is the quality of faceting and light return.

Lab-grown diamonds only come in a few shapes. False. They come in every shape natural diamonds do, from round to marquise to heart to baguette.

All lab-grown diamond shapes cost the same. Round still tends to cost the most per carat, though the gaps are flatter than in natural diamonds.

Fancy shapes are lower quality than round. No. They are simply faceted differently. Quality depends on cut, not shape.

A bigger carat always looks bigger. No. Shape and proportions drive face-up size. A one-carat marquise looks larger than a one-carat round.

Lab-grown diamonds fade or change over time. Lab-grown diamonds are genuine diamonds. They do not fade, cloud, or change.

Conclusion

Shape is the most personal, character-defining choice in a diamond. Every shape has its own quiet beauty. Round offers timeless brilliance. Oval brings modern elegance. Emerald delivers architectural refinement. Pear and marquise make a statement. Cushion and Asscher carry vintage warmth.

Lab-grown diamonds give Australian buyers the freedom to choose the shape they truly love, often at a size or quality not previously within reach. Shape is one note in a four-part harmony alongside cut, colour, and carat. Choose the shape that feels like home.

Explore LOHR's collections or book a consultation to see the shapes in person.

FAQs on Lab-Grown Diamond Shape

What is the most popular lab-grown diamond shape?

Round brilliant remains the most popular overall, prized for its unrivalled sparkle and timeless appeal. Australian commentary places it at roughly half the market. Oval is the fastest-rising favourite, now the leading fancy shape in Australia, loved for its modern, elongated look.

What is the difference between a diamond's shape and its cut?

Shape is the diamond's outline, such as round, oval, or emerald. Cut is how skilfully the stone is faceted, proportioned, and polished to return light. The terms are used interchangeably in everyday speech, but a formal cut grade is only assigned to round brilliants. Fancy shapes are judged on proportions, symmetry, and polish.

Which lab-grown diamond shape looks the biggest?

Marquise looks the largest for its carat weight, thanks to the greatest face-up surface area, followed by pear and oval. Emerald and elongated radiant or cushion shapes also appear generous. Round, princess, and Asscher tend to look smaller per carat.

Which lab-grown diamond shape is the best value?

Fancy shapes, especially emerald, cushion, radiant, princess, marquise, and pear, generally cost less per carat than round, which wastes the most rough. With lab-grown diamonds, prices are far lower across every shape, so buyers can often choose a larger or higher-quality stone, whatever the shape.

Do all lab-grown diamond shapes cost the same?

No. Round brilliants typically cost the most per carat, both because cutting a round wastes more rough and because demand is highest. Fancy shapes usually offer better value, though lab-grown diamonds narrow the gaps considerably.

Which lab-grown diamond shape hides inclusions best?

Brilliant cuts hide inclusions best. Round, oval, princess, and radiant scatter light in a way that masks small flaws. Step cuts such as emerald and Asscher reveal everything through their open facets, so they need higher clarity to look clean.

Which lab-grown diamond shape sparkles the most?

The round brilliant sparkles the most, with 57 to 58 facets engineered for maximum brightness and fire. Among fancy shapes, radiant, oval, and princess deliver excellent brilliance. Step cuts such as emerald and Asscher trade sparkle for elegant, mirror-like flashes.

What is the best lab-grown diamond shape for an engagement ring?

There is no single best shape. It depends on personal style, hand shape, lifestyle, and budget. Round suits classic tastes. Oval flatters most hands. Emerald offers refined elegance. Pear or marquise makes a statement. The best shape is the one that feels right for the wearer.

What is the bow-tie effect, and which shapes have it?

The bow-tie effect is a dark shadow across the centre of elongated brilliant shapes, especially oval, marquise, and pear. It is caused by light leaking rather than reflecting back. A faint bow-tie is normal. A harsh one signals a poorer cut. Bow-tie is not noted on certificates, so viewing the stone first is essential.

Are lab-grown diamonds available in every shape?

Yes. Lab-grown diamonds are cut into the same shapes as natural diamonds, including round, oval, princess, cushion, emerald, pear, radiant, Asscher, marquise, heart, and accent shapes such as baguette and trillion. They are real diamonds, so the cutting process is identical.