Lab-Grown Diamond Cut Explained

Lab-grown diamond cut refers to how the grown rough diamond has been planned, faceted and polished into a finished gemstone. The diamond-growth method does not automatically determine cut quality.

A CVD-grown diamond can be beautifully cut or poorly cut. An HPHT-grown diamond can also be beautifully cut or poorly cut.

Once the rough crystal has been produced, cutters still have to decide how to orient it, what polished shape to create, what proportions to use and how accurately the facets should be finished. Those decisions influence how the finished diamond handles light.

GIA describes three major visual components associated with diamond cut: brightness, meaning white light returned from the diamond; fire, meaning flashes of spectral colour; and scintillation, meaning the flashes and contrasting light-and-dark pattern visible as the diamond, observer or light source moves.

A strong cut balances these effects rather than maximising one number in isolation.

This distinction should be clear throughout the Aurelia article.

Shape describes the diamond's outline and general faceting style. Examples include round, oval, pear, marquise, cushion, emerald, Asscher and princess.

Cut quality describes how well the polished diamond's proportions, facet relationships and craftsmanship work together.

A diamond can therefore be: an oval brilliant by shape and cutting style, while still having stronger or weaker overall cut execution.

Likewise, an emerald cut describes a rectangular step-cut style. It does not automatically tell you whether the individual diamond has attractive proportions, symmetry or light behaviour.

The phrase "round cut diamond" is often used casually, but the more precise common description is round brilliant diamond.

Neither in the sense buyers sometimes assume.

Round describes the outline. Brilliant describes the faceting style designed to produce substantial brightness, fire and scintillation. A standard round brilliant normally contains 57 or 58 facets depending on whether a culet facet is present.

Its overall quality can then receive a formal cut grade from laboratories whose grading system applies to that diamond.

A clearer sentence would be: "IGI evaluates round brilliant diamonds using its own cut-grading methodology, while polish and symmetry are also reported separately."

Colour and clarity describe important characteristics, but neither alone determines how effectively a diamond returns light.

A very high-colour, very high-clarity diamond can still look comparatively flat if its geometry produces weak light return. A diamond with slightly lower colour or clarity can appear substantially more lively if it has stronger cut execution.

This is why buyers should not allocate their entire attention to carat, colour and clarity and then treat cut as an afterthought.

GIA's cut research evaluates a round brilliant's face-up appearance, design and craftsmanship rather than using only one table percentage or depth figure.

The everyday word "sparkle" combines several visual effects. Brightness is the white light you see returning from the diamond. Fire appears as flashes of spectral colour. Scintillation includes flashes and patterns created when the diamond, light or observer moves.

Facet arrangement, proportions and finish influence how these effects appear. Lighting matters as well. A diamond does not generate light itself; it redirects light from its environment.

This means a strong cut can support excellent optical performance, but the exact appearance will still vary between daylight, diffuse indoor lighting and point-source lighting.

For apparent loss of brilliance over time, continue with Do Lab-Grown Diamonds Lose Their Sparkle?

Not inherently. Laboratory-grown origin describes how the rough diamond crystal was created. Cut quality describes what happened after that rough existed.

Once laboratory-grown rough has been produced through CVD or HPHT, it still needs to be planned, shaped, faceted and polished. The cutter or manufacturing system has to decide how to distribute the rough material.

One cutting plan may preserve more carat weight. Another may produce better proportions. A third might work around an internal feature.

Therefore: growth quality and cut quality are related stages of production, but they are not the same thing.

For the manufacturing sequence, see How Are Lab-Grown Diamonds Made?

Yes. Controlled laboratory growth does not automatically create a perfectly proportioned finished gemstone. The growth process creates rough diamond material. The rough then has to be transformed into a polished stone.

If the polished diamond is too deep, too shallow, unevenly proportioned or poorly finished, its visual performance can suffer regardless of whether the rough was laboratory-grown or natural.

"Lab-grown" is not a cut grade.

GIA's formal cut-grading system applies to standard round brilliant diamonds in the D-to-Z colour range. It evaluates seven components: brightness, fire, scintillation, weight ratio, durability, polish and symmetry. Those components represent three broader areas: face-up appearance, design and craftsmanship.

GIA's overall cut-grade scale is:

These categories each cover a range of proportion combinations rather than one exact set of "perfect" dimensions. That is important. There is no single table percentage, crown angle or depth percentage that by itself guarantees an Excellent cut.

No. Ideal is not a GIA overall cut grade. GIA's formal round-brilliant cut scale runs from: Excellent → Very Good → Good → Fair → Poor.

Retailers sometimes use "Ideal", "Super Ideal" or similar terminology in their own product categorisation. Other laboratories may also use Ideal terminology within their systems.

Therefore, Aurelia should never rewrite: GIA Excellent as: GIA Ideal unless the actual laboratory documentation uses that terminology. Use the issuing laboratory's exact language.

In diamond-market language, Triple Excellent or 3EX commonly describes a GIA round brilliant that receives: Excellent overall cut, Excellent polish, and Excellent symmetry. Those are three separate recorded results.

It does not mean GIA has one grade officially named "Triple Excellent". Nor does it mean every Triple Excellent diamond looks identical. GIA itself notes that an Excellent cut grade covers a range of proportions and appearances.

So Triple Excellent can be a useful screening criterion, but it should not replace evaluation of the individual stone.

No. Excellent is a range, not one mathematical point. Two GIA Excellent round brilliants can have different tables, crown angles, pavilion angles, depths and visual personalities.

One buyer may prefer a particular balance of brightness and fire. Another may prefer a different proportion combination within the same grade.

That does not mean the grading system is unreliable. It means the grade intentionally accommodates multiple proportion sets capable of strong overall performance.

Very Good is the category immediately below Excellent in GIA's round-brilliant cut system. A Very Good stone can still be attractive. The difference may involve one or more aspects of appearance, design or craftsmanship.

It should not automatically be rejected purely because the report does not say Excellent. Likewise, a buyer should not automatically choose one Excellent diamond over every Very Good option without looking at actual dimensions, proportions and appearance.

Grades help narrow decisions. They do not replace the diamond.

Good is another formal GIA category. Compared with higher categories, compromises in light performance, proportions or craftsmanship may become more noticeable. Whether such a stone suits a particular jewellery purchase depends on the diamond and buyer.

For buyers placing strong priority on brilliance, higher cut categories will usually deserve consideration first. But Aurelia should avoid turning a grading scale into unsupported statements such as: "Good cut diamonds are bad diamonds." The terminology already tells the buyer that Good is below Very Good and Excellent.

IGI uses its own methodology. For round brilliant diamonds, IGI evaluates polish, symmetry, proportions and light performance. IGI currently states that the highest round-brilliant cut result available within its system is Excellent-Ideal. Its methodology also offers specialised light-performance analysis for qualifying diamonds.

This is precisely why laboratory names should stay attached to their terminology. A GIA Excellent grade and an IGI Excellent-Ideal result should not be casually rewritten as though they were labels from one universal scale. Each laboratory defines and applies its own system.

Do not treat them as automatic equivalents. GIA and IGI use their own research, terminology and grading methodologies. A seller should therefore reproduce the grade that appears on the actual report rather than converting it into another laboratory's vocabulary.

If the report says: IGI Excellent-Ideal — state IGI Excellent-Ideal. If another report says: GIA Excellent — state GIA Excellent.

Avoid homemade conversion tables claiming: IGI Ideal = GIA Excellent unless an authoritative source explicitly defines such a direct equivalence.

For its conventional diamond reports, GIA currently gives an official overall cut grade only to standard round brilliant diamonds. Fancy shapes—including oval, pear, marquise, cushion, emerald and princess—do not currently receive a GIA overall cut grade.

GIA does, however, report polish and symmetry for these diamonds, and buyers can evaluate measurements, outline, proportions and shape-specific visual characteristics.

This distinction should replace any older Aurelia language implying that an oval or emerald automatically receives the same GIA Excellent-to-Poor cut grade as a round brilliant.

Yes, under IGI's current methodology. IGI states that it grades fancy-shaped diamonds on an Excellent-to-Poor scale using a four-step process. That process considers polish and symmetry first, then proportion qualifications, additional shape-specific craftsmanship requirements and finally light return.

IGI specifically notes that fancy-shape cut quality cannot be judged from proportions alone. This is a major distinction between current IGI and GIA reporting and should be represented accurately.

IGI's fancy-shape framework is useful because fancy shapes have issues that cannot be reduced to one table-and-depth formula. First, polish and symmetry are considered. Then the stone's proportions are assessed against shape-specific parameters. The methodology also considers craftsmanship factors that can vary by shape, such as bow-tie appearance and girdle ranges. Finally, trained gemmologists assess overall light return.

A fancy-shaped diamond that passes the applicable requirements can receive an Excellent overall cut grade under IGI's system.

This means outdated statements such as: "Fancy shapes never receive cut grades." are now too broad. The correct statement is: "Whether a fancy shape receives an overall cut grade depends on the laboratory and report system."

In diamond terminology, shapes other than round brilliant are commonly grouped as fancy shapes. Examples include oval, pear, marquise, cushion, emerald, Asscher, princess and heart.

"Fancy shape" does not mean fancy-coloured diamond. Shape and colour are separate characteristics.

Each outline also creates its own visual considerations, which is one reason fancy-shape assessment is more complicated than applying the same round-brilliant proportion system to every diamond.

Searchers often look for a single "ideal" table or depth percentage for ovals, pears, cushions and emerald cuts. That can be useful as a rough filter, but it is insufficient by itself.

Two ovals with similar table and depth percentages can have very different: outline appeal, bow-tie visibility, facet patterns, light return and face-up spread. Likewise, two emerald cuts with similar dimensions can have very different step patterns and visual balance.

IGI explicitly states that fancy-shape cut quality cannot be graded using proportions alone. That is the correct buying principle.

For an oval, inspect more than the report numbers. The outline should look balanced to you. Length-to-width ratio affects whether the stone appears broad or slender. The shoulders should transition smoothly. Bow-tie contrast deserves attention. The facet pattern should look balanced across the stone rather than producing large lifeless areas.

A GIA report will not currently give an oval an overall cut grade. An IGI report may provide a fancy-shape cut grade under IGI's methodology. Therefore, read the actual laboratory report rather than assuming all oval diamonds are graded identically.

Elongated brilliant-style diamonds such as ovals, pears and marquises can display a darker bow-tie-shaped region across the centre. Some contrast is a natural part of many facet patterns. The issue is degree.

A severe, persistent dark bow tie can dominate the stone and reduce the balanced light return a buyer may want. A subtle bow tie may be completely acceptable or barely distracting.

This is one reason fancy-shape diamonds benefit from visual evaluation rather than being selected from dimensions alone.

A pear combines a rounded end with a pointed tip. Beyond basic proportions, buyers should consider whether the shoulders look balanced, whether the point aligns with the centre line and whether the stone displays an attractive light pattern. Bow-tie contrast can occur in pears as well.

The point also deserves adequate protection once set because pointed areas can be vulnerable to impact. Cut quality for the pear should therefore include both visual appeal and practical craftsmanship considerations.

Marquise diamonds are elongated brilliant-style stones with pointed ends. A balanced outline, attractive length-to-width ratio, even shoulders and controlled bow-tie effect are useful visual considerations.

A marquise can also deliver substantial face-up spread for its weight, which means carat weight alone should not be used to judge how large it looks.

For visible-size comparisons, see Diamond Carat Weight vs Size.

Emerald cuts are step-cut diamonds rather than brilliant cuts. Their appeal comes from broad, geometric flashes and a hall-of-mirrors effect rather than the smaller, rapid scintillation associated with a round brilliant.

Important considerations include: outline, length-to-width ratio, step pattern, windowing, light-and-dark balance, polish, symmetry and clarity visibility.

An emerald cut should not be rejected because it does not sparkle like a round brilliant. It is designed to produce a different visual style.

Asscher cuts are also step cuts. Their square or near-square outline and concentric step facets create a geometric pattern. Strong examples display an appealing balance of bright and dark reflections as the stone moves.

Because the faceting is open, inclusions and body colour can sometimes be more visible than in busier brilliant-style stones. That connects cut choice with clarity and colour considerations without making them the same characteristic.

"Cushion" covers a broad family of facet patterns. Some cushions display larger, chunkier flashes. Others use modified brilliant arrangements producing a different texture of scintillation.

That variety makes it especially risky to buy cushion diamonds using a single table/depth formula. The actual facet pattern and face-up appearance matter. A report can provide important measurements and finish information, but imagery or appropriate visual inspection remains valuable.

Princess diamonds usually have a square outline with brilliant or modified-brilliant faceting. Important considerations include balanced proportions, a symmetrical square outline and attractive light return. Their pointed corners deserve appropriate setting protection.

Again, a strong princess should be judged as a princess rather than against round-brilliant cut rules.

Polish describes the quality and condition of the diamond's facet surfaces. During cutting, facets are polished to smooth reflective surfaces. Polish grading looks for features associated with that finishing process or later surface condition. These can include polishing lines, abrasions, scratches, pits and other surface features depending on the laboratory's methodology.

Polish is therefore one aspect of craftsmanship. It is not the same thing as overall cut.

Symmetry describes the precision of a diamond's shape and facet arrangement. It considers whether corresponding facets are appropriately aligned and whether the stone's outline and facet relationships are balanced according to its design.

Potential symmetry issues can include an off-centre table or culet, irregular facets, uneven outlines or misaligned facet relationships. Again, symmetry contributes to overall craftsmanship. It is not a substitute word for cut.

These terms should remain separate on Aurelia product and educational pages.

A diamond can therefore have Excellent polish and Excellent symmetry without necessarily receiving the highest overall cut grade. Likewise, a fancy shape can carry polish and symmetry grades even when its laboratory report does not provide an overall cut grade.

No. Polish is only one component. A diamond could have extremely smooth facet surfaces but poor proportions. That stone may receive an Excellent polish grade while its overall visual performance remains weaker.

Do not see: Polish: Excellent and rewrite the product as: Cut: Excellent unless the report actually provides an Excellent overall cut grade.

Again, no. Symmetry describes one aspect of craftsmanship. An evenly aligned stone can still have proportion choices that reduce light performance. Conversely, a diamond with very strong overall performance may not need mathematically perfect facet relationships to remain attractive.

Always reproduce the actual report fields independently.

Under GIA's round-brilliant system, it is possible for Very Good polish or symmetry to coexist with an overall Excellent cut under certain conditions. GIA specifically notes that polish and symmetry contribute to the overall cut assessment but are also graded separately.

This is another reason "Triple Excellent" and "Excellent Cut" should not be treated as synonymous. Triple Excellent specifically adds separate Excellent polish and Excellent symmetry to the Excellent overall cut result.

Light return describes how effectively light entering the diamond is directed back towards the observer rather than escaping through areas that reduce the desired face-up brightness. Good light return helps create a lively appearance.

But a simplified light-return score should not be treated as the whole visual experience. Fire, contrast, scintillation pattern, proportions and personal preference also matter.

IGI's current light-performance reporting separately analyses components such as overall light performance, brightness, fire and contrast for qualifying round diamonds.

Light leakage refers to light that exits the diamond in directions that do not contribute effectively to the intended face-up return. Excessive leakage can create dark or washed-out areas and reduce visual brightness.

However, attempting to eliminate every dark area is not the goal. Contrast is important to scintillation. A diamond that returned uniform white light without contrasting patterns would not necessarily create the dynamic appearance people associate with diamond sparkle. The objective is balanced optical behaviour.

Brightness is the white light returned to the observer. A well-cut diamond can produce a crisp pattern of bright and darker areas. Brightness should not be confused with colour grade.

A G-colour diamond can have excellent brightness. A D-colour diamond can have weak brightness if its cut performs poorly. Colour and cut measure different characteristics.

Fire is the separation of white light into spectral colours. It appears as coloured flashes—often red, blue, green, orange or yellow—under suitable lighting conditions. GIA includes fire as one of the face-up appearance components used in its round-brilliant cut system.

The amount visible at any moment also depends strongly on lighting.

Scintillation describes the changing pattern of bright and dark areas and the flashes that appear as the diamond, observer or lighting moves. It is one of the reasons a diamond can look more dynamic in motion than in a still photograph.

A strong facet pattern creates organised contrast rather than random dark patches. Again, this is why a cut grade represents more than one proportion number.

Not directly, but proportions influence face-up spread. A diamond can retain excess weight in its depth or girdle and therefore appear smaller from above than another diamond of equal carat weight.

GIA includes weight ratio as one component of its round-brilliant cut assessment. This helps penalise diamonds that retain weight inefficiently relative to their visible diameter.

For the detailed relationship between weight and visible dimensions, use Diamond Carat Weight vs Size.

Yes. A shallow proportion combination can direct light in less desirable ways and create weaker contrast or light return depending on the complete geometry.

But "shallow" cannot be diagnosed from one percentage without context. Table size, crown angle, pavilion angle, girdle and other relationships work together.

Yes. Excess depth can hide weight below the face-up view, making the diamond appear smaller for its carat weight. It can also interact with other proportions in ways that reduce desired optical performance.

Again, no single depth percentage should be turned into a universal cut grade.

The table is the large top facet. Table percentage describes its size relative to the diamond's width under the applicable measurement method. It is an important proportion. It is not an independent beauty score.

Two diamonds with the same table percentage can have different crown and pavilion relationships and therefore different appearances.

Depth percentage describes the diamond's total depth relative to an applicable width measurement. It helps show how much of the stone's weight lies vertically. Like table percentage, it needs context.

Aurelia should avoid publishing simplistic rules such as: "60% depth is always perfect." Diamond geometry is interactive.

The crown is the upper portion of the diamond above the girdle. The pavilion is the lower portion beneath the girdle. In a round brilliant, the relationship between crown and pavilion angles strongly affects how light travels through the stone. One angle cannot be evaluated properly without considering the other.

GIA's cut research specifically found that no single proportion or small subset of proportions could be considered independently when judging appearance. That is an important correction to online "perfect diamond proportions" charts.

No. Multiple proportion combinations can produce excellent results. GIA's Excellent cut category covers a range rather than one exact formula. That makes sense because brightness, fire, scintillation, weight distribution and craftsmanship interact.

Aurelia should therefore avoid presenting one set of angles as: "the only perfect diamond." Use ranges as screening information where appropriate, then consider the complete report and stone.

There is no special cut grade required just because a diamond is laboratory-grown. For a round brilliant, a high cut grade can be a strong priority because cut has such a major influence on visible performance. Where a reliable laboratory assigns an Excellent or equivalent top-level result under its system, that can be useful evidence.

But "best" also depends on shape. An oval cannot be judged by simply applying round-brilliant grading rules. An emerald cut intentionally produces a different visual effect. A cushion may have a facet pattern someone prefers even if another cushion has different optics.

The best cut is therefore the one that combines appropriate laboratory information, strong visual performance and a shape/facet character you actually like.

For a GIA-graded round brilliant, Excellent is the highest formal category and deserves strong consideration when visual performance is a priority. But even within Excellent, compare individual stones. Do not assume every Excellent diamond is visually identical.

For IGI, use IGI's own current terminology. For fancy shapes, first determine whether the laboratory actually provides an overall cut grade and how that grade was derived.

The recommendation must follow the report rather than forcing every diamond into a GIA-round framework.

There is no universal answer because the terms may come from different grading systems. GIA does not use Ideal as an official overall cut grade. IGI currently uses Excellent-Ideal as its highest round-brilliant result. Retailers can also use proprietary Ideal terminology.

Therefore, the word Ideal is meaningless without knowing who defined it. Always ask: Ideal according to which laboratory or retailer?

They affect different things. Cut strongly influences light performance. Colour describes body colour. If a buyer is choosing between an extremely high colour grade with weak cut and a slightly warmer diamond with substantially better light performance, the second diamond may appear more lively.

But that does not mean colour never matters. The optimal balance depends on the individual stones and buyer.

For colour specifically, read Lab-Grown Diamond Colour Grades Explained.

Again, they answer different questions. Clarity describes inclusions and blemishes. Cut describes the design and workmanship influencing light performance.

Once a diamond is sufficiently transparent and its inclusions are not visually distracting or structurally problematic, additional clarity may offer less visible benefit than improved cut. But severe clarity characteristics can also reduce transparency. So the characteristics should be considered together rather than ranked by a universal formula.

For clarity, see Lab-Grown Diamond Clarity Grades Explained.

GIA's laboratory-grown reporting changed significantly on 1 October 2025. Eligible loose colourless-to-near-colourless laboratory-grown diamonds weighing at least 0.15 ct now receive an overall Premium or Standard Quality Assessment rather than the former natural-diamond-style nomenclature.

For round brilliants, cut is one criterion within that assessment. A Premium result requires Excellent cut for an applicable round brilliant, together with the required colour, clarity, polish and symmetry criteria. A Standard result allows Very Good cut for the round-brilliant criterion, provided the stone remains within the rest of GIA's Standard/Premium framework.

For fancy shapes, GIA's published assessment criteria use symmetry rather than an overall fancy-shape cut grade. This distinction needs to be reflected in any current Aurelia content referencing GIA lab-grown diamonds.

It does not mean Premium is simply a cut grade. Premium is the overall current GIA lab-grown quality classification. Cut is only one part of it for applicable round brilliant diamonds.

A diamond must meet all of GIA's Premium criteria across colour, clarity, polish, symmetry and applicable round-brilliant cut to receive Premium. Therefore, Aurelia should not write: "GIA Premium is the new Excellent cut grade." That would be incorrect.

Standard is also an overall classification rather than one cut grade. For a qualifying round brilliant, Very Good cut is the minimum cut criterion within the Standard framework. Other criteria involving colour, clarity, polish and symmetry also have to meet the applicable Standard/Premium ranges.

Again, the classification applies to the complete assessment.

IGI's current lab-grown report framework continues to provide detailed cut-related information according to shape. For round brilliant diamonds, IGI assesses polish, symmetry and proportions, with Excellent-Ideal currently described as its top cut result. For fancy-shaped diamonds, IGI uses an Excellent-to-Poor overall cut scale through its four-step methodology involving finish, proportion qualification, shape-specific craftsmanship and light return.

This is substantially more precise than saying: "IGI gives cut grades to diamonds." The shape and applicable methodology need to be specified.

A product page should reproduce what the laboratory actually says. If an IGI report gives a fancy-shaped diamond an Excellent cut result, use that information accurately. If a GIA report for an oval contains polish and symmetry but no overall cut grade, do not invent an Excellent Cut label based only on proportions.

Likewise, if a retailer creates its own internal cut category, it should not be presented as a GIA or IGI grade. Transparency requires keeping laboratory and retailer terminology separate.

For a round brilliant with a respected laboratory cut grade, the report can provide very useful screening information. Even then, GIA recommends looking beyond the numbers because diamonds within a cut-grade category can display different appearances.

For fancy shapes, visual assessment becomes even more important because outline, facet pattern and shape-specific effects can vary substantially. Videos, imagery and appropriate professional assessment can therefore complement the report.

For remote buying, continue with How to Choose Diamond Jewellery Without Seeing It in Person.

A photo can help evaluate outline and certain visible features, but one still image cannot fully demonstrate scintillation or performance in motion. Lighting, exposure and photography can also exaggerate or suppress brightness.

Video can provide additional information, but it too depends on lighting and presentation. Therefore, imagery should complement laboratory data rather than replace it.

No. The laboratory cut grade belongs to the diamond under the conditions and report service used when it was assessed. Mounting the stone does not turn a Very Good cut grade into Excellent.

However, the setting can influence how the finished diamond appears by changing surrounding reflections, visibility and how much of the stone is exposed. Diamond cut and jewellery design therefore interact visually without becoming the same specification.

A halo can create additional sparkle around a centre stone because it introduces more diamonds. It does not improve the centre diamond's actual cut. Likewise, polished white metal can add brightness around a stone without changing its facet geometry.

The complete jewellery piece may look more brilliant, but the centre diamond retains its own cut characteristics.

No. Cleaning can remove oils and residue and restore the visibility of the diamond's existing light performance. It cannot change pavilion angle, table size or facet alignment.

If a well-cut diamond looks dull after regular wear, contamination may be hiding its performance.

For that question, see Do Lab-Grown Diamonds Lose Their Sparkle?

In some situations, an existing polished diamond can be recut or repolished to change its proportions or remove damage. But recutting also removes diamond material and therefore reduces carat weight. Whether it is worthwhile depends on the individual stone.

This is specialist work and should not be presented as a routine Aurelia service unless the client explicitly offers it.

Modern diamond manufacturing combines specialist equipment, digital planning, lasers, polishing machinery and skilled human decision-making. The degree of automation varies between manufacturers.

The important point for the buyer is that a lab-grown crystal does not emerge from the reactor already shaped as a polished round, oval or emerald diamond. Cutting and polishing are separate manufacturing stages.

For the full sequence, see How Are Lab-Grown Diamonds Made?

No. CVD and HPHT describe diamond-growth processes. They do not function as cut grades. Either type of rough can be polished into a strongly or weakly cut diamond.

Buy the finished diamond based on its actual cut information and appearance rather than assuming the growth method decides light performance.

For growth-method comparison, see CVD vs HPHT Lab-Grown Diamonds.

Aurelia should use the terminology from the specific laboratory report or verified product specification. For a GIA standard round brilliant carrying a qualifying cut grade, report that grade accurately. For a current IGI round or fancy-shape report, use the IGI terminology actually provided. For a GIA fancy shape with no overall cut grade, do not fabricate a cut grade from table/depth measurements.

Polish and symmetry should also be shown as separate specifications where known rather than folded into one generic "cut" label.

Most importantly, avoid a catalogue-wide statement such as: "Every Aurelia diamond is Ideal Cut" unless there is verifiable product-level evidence and a clearly defined grading source behind that claim.

"Oval cut", "pear cut" and "emerald cut" are common consumer expressions. But a buyer still needs to understand the difference between the stone's shape/cutting style and the quality of its execution.

An oval does not become excellent simply because it is oval. An emerald cut does not carry an overall GIA Excellent cut grade merely because the word "cut" appears in its shape name.

They do not. GIA currently uses Excellent through Poor for applicable standard round-brilliant cut grading. IGI uses its own methodology and terminology, including Excellent-Ideal for top round-brilliant cut and an Excellent-to-Poor fancy-shape system.

Use the laboratory named on the report.

Ideal may refer to an IGI result, another laboratory's terminology or a retailer-created category. Without the source, it is ambiguous. Aurelia should therefore always qualify the term when it is used commercially.

Fancy-shape beauty involves more than two percentages. Outline, facet arrangement, bow-tie effect, symmetry, light return and personal shape preference can all matter. Use numerical filters to narrow options—not to replace evaluation.

Excellent polish does not automatically mean Excellent overall cut. Polish refers to facet-surface quality. Keep the fields separate.

The same principle applies. Symmetry describes alignment and geometric precision. It contributes to cut quality but is not automatically the overall cut grade.

Cut should be evaluated according to the individual diamond, its shape and the laboratory system used to assess it.

For standard round brilliants, formal cut grading can provide a powerful first filter. Under GIA's system, round-brilliant grades run from Excellent to Poor. Under IGI's current system, round-brilliant terminology and methodology differ, with Excellent-Ideal currently identified as its highest result.

Fancy shapes require even more care. GIA does not currently give ovals, pears, cushions, emeralds, marquises and other fancy shapes an overall cut grade. IGI does now grade fancy shapes through its own four-step system. Therefore, never assume the same label means the same thing everywhere.

And never substitute polish or symmetry for an overall cut grade.

The most useful process is to identify the diamond's shape, read the actual laboratory report, understand the laboratory's grading system and then evaluate the stone's real visual behaviour. For a round brilliant, brightness, fire, scintillation, proportions and craftsmanship all matter. For an oval, bow tie and outline become important. For an emerald or Asscher, step pattern and light-dark balance matter. For a pear or marquise, shape symmetry, tips and bow-tie effect require attention.

A strong diamond is therefore not defined by one percentage or one marketing word such as "Ideal". It is defined by how successfully its complete facet system works for that particular shape.

For the broad quality framework, continue with What Are the 4Cs of Lab-Grown Diamonds?

For colour, read Lab-Grown Diamond Colour Grades Explained.

For clarity, use Lab-Grown Diamond Clarity Grades Explained.

For visible size and proportions, see Diamond Carat Weight vs Size.

For report terminology, continue with How to Read a Lab-Grown Diamond Certificate.

And for apparent brilliance over time, use Do Lab-Grown Diamonds Lose Their Sparkle?

When considering an Aurelia Royale design, rely on the cut, polish and symmetry information verified for that specific diamond, rather than assuming one cut grade applies across the complete catalogue.

Where a design is not currently available for direct purchase, Join the Waitlist or submit an enquiry to register your interest.