Inside the Sakura Cut Lab Diamond: What 3 NGIC Certificates Reveal About Its Engineering

Open three NGIC certificates for the same sakura cut diamond shape, NPC5216, NPA8033, NPA7461, and the first thing you see on every Cut Grade line is ***. Not Excellent. Not Very Good. Three asterisks.

If you've been told a missing cut grade is a red flag, your gut clenches at that. It shouldn't. Those asterisks aren't a downgrade. They're the lab telling you, honestly, that the standard ruler doesn't fit a proprietary shape, the same logic the world's most respected labs already follow. Each of these three NGIC reports labels the stone as a "Laboratory Grown Diamond" in its Conclusion field — exactly what you'd expect from a DovEggs sakura cut lab diamond.

I went through three archive NGIC reports on the DovEggs Modified Sakura Cut to show you what the certificate is saying, and which lines you should actually be reading when you evaluate a sakura cut diamond.

Why "Cut Grade" Means Different Things for Different Cuts

GIA's cut grade scale, Excellent through Poor, was built around one shape: the round brilliant. It launched in 2006 after a study of over 70,000 observations on round brilliants, scoring brightness, fire, scintillation, weight ratio, durability, polish, and symmetry against that single facet architecture.

For everything else, the system steps aside. GIA's own published FAQ states it directly: the round brilliant is the only shape that receives an overall cut grade on a GIA report. Oval, pear, marquise, cushion, emerald, princess, none of them get one. GIA's stated reason: facet patterns and light behavior vary too widely across fancy shapes for a single scale to apply.

So when NGIC prints *** on a DovEggs Modified Sakura Cut, it's not failing the stone. It's following the same logic the most authoritative lab in the world already applies to every non-round shape. Applying that ruler to a proprietary floral cut wouldn't tell you anything useful about how the stone actually performs. For the trade-off side-by-side with the Round Brilliant , that's a separate read.

For a broader look at whether the floral cut is becoming a real category — and how to judge one without a cut grade — see our guide to the floral cut movement.

What the Three Certificates Actually Say

NGIC is an independent gemological lab based in Guangzhou, and it certifies every DovEggs Modified Sakura Cut lab grown diamond. Each report explicitly labels the stone as a "Laboratory Grown Diamond" on its Conclusion line, then grades against the GB/T 16553 and GB/T 16554 Chinese national standards plus NGIC's own Q/NGIC-GZ-001 standard. Here are the three reports.

A housekeeping note before you read the numbers: these three stones (NPC5216, NPA8033, NPA7461) are no longer in our inventory. I'm using them here as archive examples to show the consistent pattern across our Modified Sakura Cut production, not as available stock.

The *** is identical on all three, so it's not a one-off; it's how NGIC handles every sakura cut diamond from this line. Polish, Symmetry, and Finish all read Excellent, and those are the lines that apply to any cut. Table and Depth sit higher than the Round Brilliant comfort zone, which is a design choice, not a slip.

What the Table % and Depth % Actually Mean for the Look

A Round Brilliant earns its Excellent cut grade inside a relatively tight band: GIA recognizes roughly 52–62% table and 58–63% depth as EX. DovEggs' own Excellent-cut Round Brilliant lab diamonds sit right inside it, 61% table with depths between 58.8% and 62.5%, all certified EX by NGIC. Push the table past 62% or the depth past 63% and the cut grade typically steps down, because the facet architecture isn't aimed at those proportions anymore.

The Modified Sakura Cut isn't optimizing for the same outcome. Its petal-shaped facet pattern needs visible surface area to read as petals. Squeeze the table into Round Brilliant EX territory and the bloom disappears under the crown. Across the three Modified Sakura Cut certs, table sits at 66%, 69%, and 63%, at or beyond the RB EX upper edge of 62% , wider on purpose so the petal geometry stays legible face-up.

Depth tells the same story. At 65.0%, 68.6%, and 62.7%, two of these stones run past the Round Brilliant EX upper limit of 63%, and the third sits right at the boundary . The extra depth lets the pavilion bounce light through overlapping petal segments, producing the soft, watercolor-style glow these cuts are known for instead of sharp pinpoint scintillation. Deeper because the visual goal demanded it.

Read these two numbers across stones in the same cut family, not against a Round Brilliant benchmark. The three certs show that consistency.

Why Polish / Symmetry / Finish All Excellent Matters More Than "No Cut Grade"

If I were buying one of these myself, I'd skip straight to Polish, Symmetry, and Finish on the certificate. Those three lines survive when the overall grade doesn't apply.

Polish measures how cleanly each facet was finished. Symmetry measures how precisely those facets meet. Finish bundles the broader craftsmanship picture. All three are shape-agnostic, so they work on a round brilliant, an emerald cut, or a proprietary floral cut, and all three pass or fail based on whether the cutter knew what they were doing.

Across NPC5216, NPA8033, and NPA7461, every one of those lines reads Excellent. Nine Excellents in a row is not a coincidence. It's evidence that the Modified Sakura Cut, despite a more complex facet layout than a Round Brilliant, can hit the same craftsmanship ceiling every time.

The honest answer when someone asks how good the cut is on a sakura cut diamond: read those three lines, not the line above them.

What "Modified" Specifically Did

The word "Modified" isn't decorative. Older floral-style cuts struggle with two things: hitting Excellent on Polish and Symmetry (the petal geometry is unforgiving), and surviving daily wear without chipping where thin petal tips meet the girdle.

DovEggs reworked the facet architecture to solve both. The crown carries a complex petal arrangement of overlapping facets, sized so each plane stays large enough for a polisher to finish cleanly. That's why the certs come back Excellent on Polish. The pavilion uses a radial architecture that thickens the girdle where stress concentrates, so the cut survives a standard four- or six-prong setting the same way a Round Brilliant does.

I'm not going to give you a facet count or specific crown and pavilion angles. Those figures aren't on the certificate and they're proprietary. What I can show you is the engineering result, line by line, which is what the table above does. The three asterisks aren't hiding work. They're sitting next to it, on lines the system can actually grade. Lab grown production also lets DovEggs control crystal consistency batch to batch, which is part of why Polish, Symmetry, and Finish come back Excellent every time on a sakura cut lab diamond.

What to Actually Look For on a Sakura Cut Diamond Certificate

Don't ask "what's the cut grade?" on a sakura cut diamond. Ask whether Polish, Symmetry, and Finish are all Excellent, and whether table and depth sit in a consistent band across the cut's archive, not against a Round Brilliant benchmark. Those are the lines the NGIC certificate can answer honestly.

The *** isn't a downgrade. It's the same answer GIA gives for every non-round shape on the planet. Every Modified Sakura Cut lab grown diamond from DovEggs ships with an NGIC certificate — labeled "Laboratory Grown Diamond" on its Conclusion line — so you can verify these patterns yourself. Pull up the full DovEggs Modified Sakura Cut collection and read the live cert on any stone the same way I just read these three.

If you're ready to see the certificate before you commit, browse the collection and open any stone's NGIC report — the same three lines will be waiting for you.

Sources

• GIA, "GIA Diamond Cut Grade: Six Things to Know": methodology and 5-step scale (EX/VG/G/F/P) for round brilliant cut grading

• GIA FAQ, "Is there a cut grading system for fancy shaped diamonds?": confirms GIA does not issue an overall cut grade for non-round shapes

• GIA, "Diamond Anatomy Explained": published proportion measurements including table % and depth %

• GIA, "Estimating a Cut Grade" booklet: round brilliant table % and depth % ranges by grade

• American Gem Society, "Round Guidelines": AGS Ideal cut proportion ranges (AGS Laboratories grading now administered by GIA since 2022)

• Chinese national standards GB/T 16553 and GB/T 16554, and NGIC internal standard Q/NGIC-GZ-001: normative references printed on the three NGIC certificates (NPC5216, NPA8033, NPA7461) used as the primary data in this article

Frequently Asked Questions

Q: What does the *** on the Cut Grade line of an NGIC certificate actually mean?

A: It means the lab is telling you that the standard cut grade scale (Excellent through Poor) doesn't apply to this shape. That scale was built for the Round Brilliant. For any proprietary or fancy shape, the lab leaves the Cut Grade line as *** rather than forcing the wrong measurement onto the stone. GIA does exactly the same thing — they simply don't issue an overall cut grade for non-round shapes either. On a Modified Sakura Cut, what you read instead are Polish, Symmetry, and Finish, which apply to any cut.

Q: Why does DovEggs use NGIC instead of GIA for these certificates?

A: GIA, as a policy, does not issue an overall cut grade for any non-round shape, including the Modified Sakura Cut. For a proprietary cut, sending a stone to GIA would still come back without a cut grade — but with less detail on the shape-specific characteristics. NGIC grades against the GB/T 16553 and GB/T 16554 Chinese national standards plus its own Q/NGIC-GZ-001 standard, and produces a report that documents the proprietary shape directly. That makes the certificate more informative for this specific cut family.

Q: Should I worry that my stone doesn't have a GIA report?

A: For a Modified Sakura Cut, no. A GIA report on this stone would still show *** in the Cut Grade field, because GIA doesn't grade fancy shape cut. What you want to verify on any lab grown diamond report — regardless of which lab issued it — is that Polish, Symmetry, and Finish are all Excellent, that the proportions are documented, and that the lab is independent of the seller. NGIC is independent of DovEggs and grades against published Chinese national standards.

Q: What's the difference between NGIC and NGTC?

A: They are two different labs. NGTC (National Gemstone Testing Center) is a separate organization based in Beijing. NGIC (National Gemstone Identification Center) is the Guangzhou-based lab that certifies DovEggs Modified Sakura Cut diamonds, grading against the Q/NGIC-GZ-001 standard along with GB/T 16553 and GB/T 16554. If you read an article comparing Chinese gem labs, check carefully which lab name is being discussed.

Q: Are those table and depth percentages (63% to 69%) considered acceptable in the trade?

A: For a fancy shape diamond, yes. The 52–62% table and 59–63% depth ranges that get cited as "ideal" are specifically the Round Brilliant ideals. Fancy shape diamonds — oval, cushion, marquise, and proprietary cuts — operate in different proportion bands because their facet architectures are aiming at different visual outcomes. Read the proportions on a Modified Sakura Cut against other Modified Sakura Cut certificates, not against a Round Brilliant benchmark.

Q: Can I see the NGIC certificate before I buy a stone?

A: Yes. Every Modified Sakura Cut diamond DovEggs sells ships with its NGIC certificate, and we publish the certificate image on the product page so you can review every field before you order. If you have a specific number you'd like documented in advance — say, you only want stones with Table % below 67% — you can filter by that constraint when you browse the live collection.