"Reverse Bowtie" in marquise?

[diamondhoarder]

Hi cut experts!

Years ago I had a marquise ring with a bit of a bowtie and unimpressive performance overall which I eventually sold. But I did love the marquise outline shape on my finger. Fast forward to now and I'm looking at marquises again.

I've looked at a few loose stones in person and a couple had what I could only describe as a reverse bowtie, where the belly was the brightest part of the stone.

This isn't the best pic but it gives an idea of what I mean:



Is this reverse bowtie effect considered to be desirable? I would definitely prefer to have a bright band across the diamond than a dark one.

Is it cut proportions which create this effect or the facet pattern?

 

[Karl_K]

facet pattern

Different facet pattern.
Yes they can be very nice.
In some cases the ends can be over dark in this design.
You get a bright part in center and darkness in the rest of the stone.
It needs to balance out.

 

[diamondhoarder]

Different facet pattern.
Yes they can be very nice.
In some cases the ends can be over dark in this design.
You get a bright part in center and darkness in the rest of the stone.
It needs to balance out.

Hi @Karl_K

Do you have any plots that you could post showing the difference between the facet patterns?

I just posted some pics of an LGD which I think is a similar type of cut to this in the LGD forum. If you have a moment, would you mind having a look and letting me know your opinion on it please?

 

[tyty333]

The stone you posted looks to be an 8 main offset from the center. Pretty standard for most marquises.

Here is an 8 main that is not offset from the center

https://www.jamesallen.com/loose-diamonds/marquise-cut/1.01-carat-e-color-vs1-clarity-sku-23364551

Here are a couple of 6 mains

https://www.jamesallen.com/loose-diamonds/marquise-cut/1.01-carat-d-color-si1-clarity-sku-22804868

https://www.jamesallen.com/loose-diamonds/marquise-cut/1.01-carat-g-color-si1-clarity-sku-23574741

4 main (I usually find these in shallower depths)

https://www.jamesallen.com/loose-diamonds/marquise-cut/1.01-carat-h-color-vs2-clarity-sku-24511057

https://www.jamesallen.com/loose-diamonds/marquise-cut/1.00-carat-g-color-vs1-clarity-sku-24381452

 

[Karl_K]

This is an oval but the idea is the same.
Point A is rotated to point B changing the orientation of the facets.

 

[tyty333]

This is an oval but the idea is the same.
Point A is rotated to point B changing the orientation of the facets.

This is what I've been calling "offset from the center". Is there a real name for it, though? It really would make them easier
to talk about!

 

[Karl_K]

This is what I've been calling "offset from the center". Is there a real name for it, though? It really would make them easier
to talk about!

I usualy call them "rotated pavilion" but lets check with Garry and Dave if there is a more official name:
@Garry H (Cut Nut) @oldminer

 

[Garry H (Cut Nut)]

I usualy call them "rotated pavilion" but lets check with Garry and Dave if there is a more official name:
@Garry H (Cut Nut) @oldminer

I think the whole thing is confusing and none of these approaches rules out bow ties.
This is called Oval Brilliant by both the GIA and IGI - and has 4 mains with a wide main on the side but has a sort of keel rather than meeting at the culet:


But see if you can pick the mistakes in the GIA's and IGI's plots?


And here is the twisted, rotated regular oval you are all discussing - Both called also Oval Brilliant.
See how many plot errors in both the IGI and GIA?

 

[Jobis]

I believe this is what is happening with the marquise I just bought maybe. It caught my eye because it did not have much of a bowtie online, but in person, I am disappointed with the light performance and overall the stone looks really dark to me (see the last photo, idk why it posted last, but the everything besides the bowtie is dark gray)

I am also almost certain that some of it is light leaking. See I can see through the stone in the wings area and just north and south of the center, the big pavilion main facets (see the picture on the green sticky note)

I’m going to return it most likely.

Anyone have any thoughts? Was about to make my own post about this
@Garry H (Cut Nut) @Karl_K @tyty333

 

[Garry H (Cut Nut)]

I believe this is what is happening with the marquise I just bought maybe. It caught my eye because it did not have much of a bowtie online, but in person, I am disappointed with the light performance and overall the stone looks really dark to me (see the last photo, idk why it posted last, but the everything besides the bowtie is dark gray)

I am also almost certain that some of it is light leaking. See I can see through the stone in the wings area and just north and south of the center, the big pavilion main facets (see the picture on the green sticky note)

I’m going to return it most likely.

Anyone have any thoughts? Was about to make my own post about this
@Garry H (Cut Nut) @Karl_K @tyty333

I think that is as good as Marquise get.
Later at laptop I will send some more info

 

[Garry H (Cut Nut)]

Firstly: There is no easy way for a long brilliant cut style diamond to overcome being too deep and too shallow at the same time:

 

[Garry H (Cut Nut)]

Secondly - depending on where the light is coming from, if it is spots or diffused and how close the observer or camera is, and the color of the camera (or face and hair) as to how the diamond appears.

 

[Jobis]

I think that is as good as Marquise get.
Later at laptop I will send some more info

@Garry H (Cut Nut)
Do you think it’s worth keeping this marquise then for my partners engagement ring? I was thinking about returning it in hopes I could learn more and find out how to pick out a better one from online videos. But I hope I am just stressing for no good reason and it’s fine.

Also I have a physics question for you that I’ve been trying to understand. Interestingly, I have come to learn a few things about the light performance on this diamond:

1) the wings area and the reverse bow tie area seem to leak light… through the table I can see past the diamond at certain angles in multiple spots. I also confirmed this with a little pinhole-torch experiment where I used a bright pen light and tried to assess where the small beam of light was getting through.

However!
2) in what seems like these same areas, the diamond does as you say: it reflect the color of my phone which is light/silverish blue. When I used an orange phone it was bright orange in all the same areas that I thought were leaky.



3) still yet… in what to me looks like the same facets/areas of the stone. Under direct sunlight seem to be the areas that show the most fire:

So what is going on here? Maybe they aren’t the same facets doing these things and I’m mistaken. Or maybe light is both leaking and reflecting through the same facets?

Or maybe I’m just a silly man playing with lights and shiny things!

 

[Rockdiamond]

I’m with Garry on this one. So much great info in this thread.
Based on the pics- seems like really nice MQ.
As has been pointed out- anyone who really loves a marquise shape will have to “overlook” aspects like minor leakage. I used quotes because “regular” people …. Those not reading this sort of analysis- will find that minor leakage an element of a shape they love.
There is no “perfect” marquise

 

[Garry H (Cut Nut)]

@Garry H (Cut Nut)
Do you think it’s worth keeping this marquise then for my partners engagement ring? I was thinking about returning it in hopes I could learn more and find out how to pick out a better one from online videos. But I hope I am just stressing for no good reason and it’s fine.

Also I have a physics question for you that I’ve been trying to understand. Interestingly, I have come to learn a few things about the light performance on this diamond:

1) the wings area and the reverse bow tie area seem to leak light… through the table I can see past the diamond at certain angles in multiple spots. I also confirmed this with a little pinhole-torch experiment where I used a bright pen light and tried to assess where the small beam of light was getting through.

However!
2) in what seems like these same areas, the diamond does as you say: it reflect the color of my phone which is light/silverish blue. When I used an orange phone it was bright orange in all the same areas that I thought were leaky.



3) still yet… in what to me looks like the same facets/areas of the stone. Under direct sunlight seem to be the areas that show the most fire:

So what is going on here? Maybe they aren’t the same facets doing these things and I’m mistaken. Or maybe light is both leaking and reflecting through the same facets?

Or maybe I’m just a silly man playing with lights and shiny things!

You are having so much fun. Are you a physicist by career or just by nature Hoarder?
I think you ned an ASET or the kit.

Expert ASET scope kit - Ideal Scope

ASET scope is best used for fancy shaped diamonds and super ideal cut rounds. The LED 10X top quality loupe makes it easy to examine diamonds for non-experts and the UV light enables you to check diamond fluorescence. The tweezers and stone holder & ideal and average cut CZ on the mobile phone...

ideal-scope.com

 

[Jobis]

You are having so much fun. Are you a physicist by career or just by nature Hoarder?
I think you ned an ASET or the kit.

Expert ASET scope kit - Ideal Scope

ASET scope is best used for fancy shaped diamonds and super ideal cut rounds. The LED 10X top quality loupe makes it easy to examine diamonds for non-experts and the UV light enables you to check diamond fluorescence. The tweezers and stone holder & ideal and average cut CZ on the mobile phone...

ideal-scope.com

Haha it is fun! But I was also stressing out big time about potentially getting a bad one. But I’m not too worried about that now.

I would love to have one of those kits, and could definitely get into this stuff more, but after my wife gets her ring I won’t see much utility in learning more or buying more stones. Which is sad in a way because I like the science of it and trying to optimize it all.

 

[Jobis]

I’m with Garry on this one. So much great info in this thread.
Based on the pics- seems like really nice MQ.
As has been pointed out- anyone who really loves a marquise shape will have to “overlook” aspects like minor leakage. I used quotes because “regular” people …. Those not reading this sort of analysis- will find that minor leakage an element of a shape they love.
There is no “perfect” marquise

That makes sense. Thank you for your input!

 

[Garry H (Cut Nut)]

Haha it is fun! But I was also stressing out big time about potentially getting a bad one. But I’m not too worried about that now.

I would love to have one of those kits, and could definitely get into this stuff more, but after my wife gets her ring I won’t see much utility in learning more or buying more stones. Which is sad in a way because I like the science of it and trying to optimize it all.

You could hang around here and help others. Most of those who do that have your natural enquiring mind.
I already had a lot of knowledge when this forum Began 22 years ago. But every month I learn more because answering questions requires digging deeper.

 

[Jobis]

You could hang around here and help others. Most of those who do that have your natural enquiring mind.
I already had a lot of knowledge when this forum Began 22 years ago. But every month I learn more because answering questions requires digging deeper.

That is a good point!