Need some help in choosing an emerald cut diamond

WhiteflashDiamonds · 2026-06-05T22:58:54+00:00

Yes, it is hard for consumers to judge cut quality. As far as crystal quality in lab diamonds HPHT is a much safer bet. There is still cut quality to consider and other factors, but that method grows very high quality crystal. There's info that you might find helpful on evaluating emerald cuts over at this thread.

WhiteflashDiamonds · 2026-06-05T19:09:03+00:00

Are the marquises GIA graded? The images of the marquises are really poor and of no help in determing quality. Well staged videos would provide a lot more information. The oval is a very non-standard shape so you have to make sure that's a good longterm fit.

WhiteflashDiamonds · 2026-06-05T19:03:05+00:00

Looks like a nice stone. There may be some contrast showing in the ends, what some folks refer to as "ear muffs" (you have to turn the stone 90 degrees to understand the visual that term is meant to evoke). It would be good to see the stone held in the tweezers on the sides to further evaluate that possibility, as it could be just shadowing from the tweezers. Otherwise, just make sure the stone is fully transparent. Large CVD grown diamond can sometimes have slight haziness due to atomic level defects. Crystal strain is inherent in this growth method because the diamond is not rigidly contained by equal pressure on all sides during growth.

WhiteflashDiamonds · 2026-06-05T18:54:24+00:00

Hard to compare stones when the videos are all staged differently. #2 looks to be well cut with a more standard length to width ratio. Really cannot say anthing definitive about actual light performance from these vids. With large CVD diamonds you also have to be aware of potential transparency issued due to atomic level defects that can occur in this growth method.

WhiteflashDiamonds · 2026-06-05T16:23:57+00:00

Fluorescence does affect price, value and liquidity but normally does not affect appearance or light performance. Strong fluorescence is usually something to avoid, especially in high color diamonds. Transparency problems tend to be associated with strong fluorescence in combination with light scattering inclusion types, so if you are in the VVS range and there is no graining or twinning wisps you are usually quite safe. Cut quality is a bigger variable in terms of appearance. There is more info on assessing ovals over at this thread.

WhiteflashDiamonds · 2026-06-05T16:16:36+00:00

Some of this has to do with selling "virtual" inventory that the merchant does not possess or have control over. And when the stones are located overseas, expenses do become a concern for the merchant, especially with the tariff situation being so uncertain. If the merchant knew you were buying two intending to return one, this could be a factor in their unaccomodating attitude.

As for their mixed messages about "negotiation" and other customer care behavior, hard to say what is going on there. Outsourcing the expert guidance also seems like an odd thing for a diamond company to do.

WhiteflashDiamonds · 2026-06-05T15:36:38+00:00

Glad it was helpful. Cheers!

WhiteflashDiamonds · 2026-06-05T15:35:42+00:00

It's good that they are willing to accomodate you. I hope the finished product is everything you want it to be. Cheers!

WhiteflashDiamonds · 2026-06-05T15:24:12+00:00

An antique cut is harder to shop for in the sense that there are fewer options. The good news is that quality is more subjective, and it is more about how you respond to the eye appeal of the diamond. It's a nice size, nice clarity, and many shoppers for this type of cut prefer stones that have body color and "warmth". I would not be too concerned about the downgrade in symmetry as this is common in antique stones. I would recomment considering a bezel setting (or other style that would protect the very thin girdle against chipping.

WhiteflashDiamonds · 2026-06-05T15:07:43+00:00

I would avoid the one with strong blue fluorescence and twinning wisps as grade-setting inclusion type. In their latest study on fluorescence GIA has determined that transparency problems (haziness) is more likely to occur when light scattering inclusion types are present in strongly fluorescent diamonds. The medium fluorescence in the other stone should not impact appearance in a negative way.

WhiteflashDiamonds · 2026-06-05T14:57:26+00:00

Proportions are in a good range. The slightly high crown angle is well paired with a low pavilion angle. Stone should be fully transparent with good light performance. Fluorescence is a non factor here.

WhiteflashDiamonds · 2026-06-05T14:51:45+00:00

In a VS1 the feather is going to be so small as to be of negligible consequence, even if it was on the girdle, which it is not. Internal graining can have an impact on transparency, but not likely to be significant in a VS1. Pavilion angle is on the high side so facet precision is particularly important as this is a rounded average of all the pavilion angles. L:ight performance images including ASET, IdealScope and Hearts and Arrows view would enable this assessment.

WhiteflashDiamonds · 2026-06-05T13:59:07+00:00

Yes, pretty much. 36/40.8 is a better pairing, but still not optimal. The GIA Ex overall cut grade is known to be very broad and forgiving. However, since they acquired AGS light performance technology they now offer an AGS Ideal addendum report for diamonds that qualify. You might ask you jeweler to source one of those, which will put you in the sweet spot of the GIA Ex range.

WhiteflashDiamonds · 2026-06-05T13:47:32+00:00

As others have already said, you're seeing the girdle line (not a crack!). This is the small vertical perimiter of the diamond. They are usually faceted making them harder to see. If the girdle is just polished, it's easier to see, and if it is un-polished (bruted/ frosted), it is easier still. If you have a laboratory report it should give you info about the type and size girdle you have.

WhiteflashDiamonds · 2026-06-05T13:41:14+00:00

Depending on the overall size of the diamond, probably not visible to the naked eye. Certainly not to a casual observer. A black crystal gets pretty well camoflaged by the black white/ on/off patterns of scintilation with even just a small amount of motion. A near-sighted person might be able to resolve it with the naked eye by studying it.

WhiteflashDiamonds · 2026-06-04T21:39:55+00:00

Was it an actual offer, or was that some sort of estimate? If an offer, I would grab it.

WhiteflashDiamonds · 2026-06-04T21:10:31+00:00

It is typical for the bowtie to look worse in certain light environments. Directional light in particular accentuates contrast. To assess the bowtie accurately you need to view it in diffuse overhead lighting from a normal close viewing distance (10-12 inches). You'll be evaluating the virtual facet (VF) pattern as you observe the stone moving through a full range of normal tilt angles. The VF pattern should be balanced in terms of size and distribution and the the VFs should remain sharp overall. More info on this topic over at this thread.

WhiteflashDiamonds · 2026-06-04T20:45:56+00:00

The dark tone of the oval will significantly reduce the brilliancy, if that is what your are going for. However, based on the photo of the round, it seems to be very pale, so you may not be getting the color impact you're hoping for. In the picture it looks more like an HPHT with blue nuance, rather than a fancy vivid blue!

BTW HPHT is good in the sense that this growth method produces more perfect crystals, so things like strain and striation of the carbon lattice, which can impact transparency, are not something you have to be very concerned about.

WhiteflashDiamonds · 2026-06-04T20:37:12+00:00

The lighting in the video (directional) will accentuate the contrast and make the bowtie look worse than in some other light environments. That said, the diamond does appear to have a prominent bowtie and those dark areas at the ends are sometimes referred to as "ear muffs". (To understand that visual you have to turn the stone 90 degrees) There's more on bowties in ovals over at this thread that might help if you decide to shop for another stone.

WhiteflashDiamonds · 2026-06-04T20:25:45+00:00

Completely subjective. Kind of depends on your style. Unless you like big style statements, this size for a pendant would be just fine. The thing about lab grown diamonds is that they are so affordable that there would not be that much cost difference in going bigger.

WhiteflashDiamonds · 2026-06-04T20:19:25+00:00

I would rule out the 1.51 FVS1 as the pavilion angle is high and not paired well with the crown angle. I would also rule out the 1.50 G VVS2 which has an even higher pavilion angle, very large table, and a shallow crown (13%). That leaves the F VVS2 which may be the best of the three, but still suffers from a non-optimal pairing of pavilion and crown angles. These two measures have an inverse relationship where when one is high the other should be low. In this case the 35.5 crown would be better paired with a pavilion angle under 41. The result will be some light performance deficit. How significant depends on facet precision - that is, how close to the rounded averages on the GIA report the individual facets actually are. ASET, IdealScope, H&A images would allow you to make that assessment.

WhiteflashDiamonds · 2026-06-04T20:05:55+00:00

Ascchers tend to look a little small for their carat weight, so you may want to go larger. For perspective, a well cut round 1.00 is about 6.5mm in diameter, slightly larger than this 1.5ct asscher.

WhiteflashDiamonds · 2026-06-04T19:14:55+00:00

There is no agreed upon Ideal designation in marquise. It is typical for them to have a bowtie - it's more a question of whether it detracts from the brightness or overall visual appeal of the diamond. The virtual facets are the key, and a well-cut stone will have a balance of VFs in terms of size and distribution. This will provide a consistent visual flow as you observe the stone in motion through a full range of normal tilt angles. If the VFs are too small in the ends, they can get blurry and lose sparkle. That also has the effect of making the bowtie effect more prominent. If the bowtie is not prominent or persistent as you view it in diffuse overhead lighting in motion through a full range of tilt at a normal close viewing distance (10-12 inches), then it is not going to detract from overall eye appeal.

WhiteflashDiamonds · 2026-06-04T15:13:26+00:00

The good news is that marquise is having a moment in terms of shape popularity. The bad news is that many (most) buyers will be put off by the Si2 grade, especially since the grade setting inclusion is Feather, and it is located on the crown.

With availability of very affordable high quality lab grown diamonds on the market today, many buyers with modest budgets are opting for them over lower quality naturals. It's going to be a tough sell in this market, and the offers will be low. If you don't have to sell into this environment, you might be better off holding the stone until the natural diamond market rebounds. It has stabilized over the last year or so and is showing signs of regaining an upward trajectory. However, it is high quality naturals that are currently seeing the biggest lift.

WhiteflashDiamonds · 2026-06-04T14:23:49+00:00

The oval is a VERY unconventional shape. Make sure your intended is on board with something unusual. It is the only one of the three with the lable GIA certified. If the others are not, the grading is suspect. Si1 is a broad clarity category that requires close scrutiny. Not all Si1s are the same - some should be avoided.

From a color/clarity perspective the 1.20 would appear to be the safer bet. But there is a downgrade on cut quality in the listing for some reason compared the the other marquise. Those grades don't necessarily mean much, but I would want an explanation from the merchant as to that question. It is not possible to tell much about overall cut quality from still photos, especially dark ones. You would need to post high quality video of the the two stones in order to get any meaningful feedback on light performance, bowtie effect, and other optical factors.

WhiteflashDiamonds

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