Oval diamonds
Where Inclusions Hide in an Oval
The clarity grade is one letter. The plot diagram beside it is a map β and on an oval, position beats grade more decisively than on any other shape.
Written by the Mapple Gems workshop, Surat Β· Updated 22 August 2026
Short answer
On an oval, an inclusion under the table is exposed and one near the outline or in the bow-tie zone is largely hidden. That means a well-placed SI1 routinely outperforms a badly-placed VS2 and costs less. Open the plot diagram: red marks internal features, green surface ones. The two questions are whether it sits under the table and whether it is visible unmagnified.
Clarity is the grade people optimise hardest and understand least. It is assessed at exactly 10Γ magnification, which means seeing an inclusion under a loupe is not a discovery β it is what the grade already predicted. What matters is whether you can see it at arm's length, on a hand, in a room.
On an oval that depends far more on where the inclusion is than on which letter the report prints.
Reading the plot
Every IGI or GCAL report carries a plot diagram, and hardly anyone opens it. It is a drawn outline of the stone with its features marked in two colours: red for internal inclusions, green for surface features such as naturals or extra facets.
Note that lab grown reports from GIA changed in October 2025 β those now carry a Premium or Standard quality assessment rather than letter grades, while IGI and GCAL still give the granular 4Cs and the plot. Since IGI grades most lab grown production, the plot is usually available. If you are handed a report without one, ask why.
The oval-specific map
| Where it sits on the plot | Visibility face-up | What to do |
|---|---|---|
| Centre of the table | Worst case β fully exposed | Reject regardless of grade |
| In the bow-tie zone, across the waist | Well hidden β the dark band absorbs it | Genuine bargain territory |
| Near the outline, mid-side | Usually hidden by scattered brilliance | Fine; confirm on video |
| On or near the girdle | Hidden β and coverable | Ask for a prong oriented over it |
| At either tapered tip | Hidden, but structurally relevant | Fine unless it is a feather reaching the surface |
| A large feather reaching the surface, near a tip | Invisible | Reject β this is a durability question, not a clarity one |
The second row is the one worth acting on. An oval's bow-tie darkens the middle of the stone, and a dark zone is a poor place to spot anything. An inclusion sitting there is functionally invisible on a shape where you already accepted the dark band. That is not a trick β it is simply how the two features interact, and it is why an oval tolerates a lower clarity grade than a step cut ever will.
The last row is the exception that overrides all the position logic. A feather is a fracture. One that reaches the surface, near a thin tapered end, is a structural weakness in the most exposed part of the stone. Position does not save it.
The free request nobody makes
If an inclusion sits on or near the girdle, a prong can be oriented to cover it. The setter simply rotates the stone in the head so a prong lands on that point rather than somewhere arbitrary.
It costs nothing. It takes no extra time. It is available on any made-to-order ring, and almost nobody asks, because almost nobody knows the setter has a choice. On an oval it is doubly useful, because prongs belong at the shoulders anyway rather than on the tapered tips, which gives four natural positions to work with.
From our bench in Surat
Lab grown production clusters at high colour and clarity, which sounds like good news and mostly is. But it has a side effect worth naming: because so much output lands in VS and above, buyers get used to reading a clarity grade as the headline number β and cut, the one thing that actually decides whether an oval looks bright, is not graded on a fancy shape at all.
So the honest ranking from where we sit. On an oval, spend on cut first, then position, then grade. A brilliant, well-proportioned SI1 with everything tucked to the sides will beat a flat VS1 every day of the year, and it costs less. Ask us to show you the plot alongside the video β the two together answer nearly everything a report cannot.
Two lines on the report worth checking
Polish and symmetry are two separate grades. Listings quote whichever is better. Read both. And be clear about what symmetry means on an oval: it describes facet placement and outline evenness. It does not describe light performance, and an Excellent symmetry oval can still have a severe bow-tie.
The inscription is the only line tying the report to the stone. A report belongs to a stone, not to a ring, and the girdle inscription is what links them. Ask whether your oval is inscribed, and if so, ask to see the number matched to the certificate before the stone is set.
Before you approve a stone
- Open the plot. Ask where the marked features sit relative to the table.
- Check for any feather reaching the surface near a tip or the girdle.
- Ask for a prong to be oriented over a girdle inclusion, if there is one.
- Read polish and symmetry separately, not as one figure.
- Judge visibility at arm's length on video, not at 10Γ.
- Spend the clarity saving on cut, which no laboratory grades on an oval.
Frequently asked questions
What clarity grade should I buy for an oval diamond?
VS2 and SI1 are the value range on an oval, because scattered brilliance and the bow-tie together hide a great deal. Position matters more than the letter: a well-placed SI1 routinely outperforms a badly-placed VS2 and costs less.
What do the red and green marks on a plot diagram mean?
Red marks internal inclusions and green marks surface features such as naturals or extra facets. The two questions to ask of any of them are whether they sit under the table and whether they are visible without magnification.
Can a prong be positioned to hide an inclusion?
Yes, if the inclusion is on or near the girdle. The setter rotates the stone so a prong lands on that point. It costs nothing and takes no extra time on a made-to-order ring, and it is one of the least-used requests in the trade.
Which inclusion should always be rejected?
A large feather reaching the surface, particularly near a girdle or one of the oval's tapered tips. A feather is a fracture, and one at the surface in the most exposed part of the stone is a durability issue rather than a cosmetic one.
Does the bow-tie really hide inclusions?
In practice, yes. The bow-tie darkens the middle of an oval, and a dark zone is a poor place to spot anything. An inclusion sitting there is functionally invisible on a shape where the dark band was already accepted as normal.
Ask for the plot and the video together
Between them they answer nearly everything the grade alone cannot. Every piece is made to order in our Surat workshop.
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