GIA VG vs EX H&A brilliance comparison

[BL218]

I found below GIA very good cut diamond much brighter in the video than the H&A EX cut diamond. Contradict with the supposed cut grade and light performance corelation. Anyone know why?

Is it worth to pay up for a better cut?

GIA VG cut:

2.00 Carat round diamond

This 2 carat round diamond D color vvs2 clarity has Very Good proportions and a diamond grading report from GIA

www.jamesallen.com

GIA EX H&A diamond 1:

2.03 Carat round diamond

This True Hearts TM diamond, 2.03 carat D color vvs2 clarity has ideal proportions and a diamond grading report from GIA

www.jamesallen.com

GIA EX H&A diamond 2:

2.36 Carat round diamond

This True Hearts TM diamond, 2.36 carat D color if clarity has ideal proportions and a diamond grading report from GIA

www.jamesallen.com

 

[Karl_K]

The GIA Vg is going to look very dark under the table up close and in some lighting dark around the edges.
In a tiara in the right lighting its a knock out, in a ring not so much.
Its going to look small and dark under the table.

 

[MissGotRocks]

The angles don’t work well together at all. Definite pass on the GIA VG!

 

[lovedogs]

The VG won't perform well IRL at all

 

[Dreamer_D]

Those little videos can tell a lot about cut if you know what to look for. But you can’t use them to judge “brightness” as you are doing here. The lighting in those videos is not standardized.

 

[BL218]

I have also found the ideal scope of the VG cut diamond. How does it compare to a EX cut diamond below?

VG cut:

EX cut:

 

[MissGotRocks]

I have also found the ideal scope of the VG cut diamond. How does it compare to a EX cut diamond below?

VG cut:

EX cut:

You can clearly see the concentration of black in the center of the VG stone. The center of the diamond will appear darker in real life viewing. The angles on that stone are not what anyone here would recommend and there is a difference in the cut grade for a reason.

 

[BL218]

You can clearly see the concentration of black in the center of the VG stone. The center of the diamond will appear darker in real life viewing. The angles on that stone are not what anyone here would recommend and there is a difference in the cut grade for a reason.

I see. Just that I m seeing the EX cut appears to be more pale in the table so wonder if there is more light leakage in the table.

 

[DejaWiz]

I have also found the ideal scope of the VG cut diamond. How does it compare to a EX cut diamond below?

VG cut:

EX cut:

Face up Ideal-Scope results can give us a baseline idea of the light return and highlight any potential problem areas but, what it won't show, is the real world appearance...especially as the diamond is moving and tilting around like they tend to do when being worn.
An overly shallow pavilion angle will usually introduce over-obstruction, which is the darkening of the center that Karl stated.

The diamond is extremely steep and deep with a 64.4% depth. It was cut to retain as much carat weight as possible to hit that magic 2 carat mark.
Look at the diameter difference between the 2.0 VG and the 2.03 Ex = 7.86mm vs 8.15mm is a 0.29mm change in diameter, which is easily noticeable by most humans.
7.9mm is around the 1.90 carat mark for a well cut and proportioned RBC, so quite a lot of face-up size appearance is being lost with the 2.00 VG.

Now, if it were going to be purchased with the intent to recut to an antique round such as an OEC, then it's probably a good piece of rough.

However, diamonds can have that one in a million weirdo that plays by it's own rules, so maybe that 2.00 carat weight VG might be an exception to a set of very well defined and observed rules. I'm not urging you to buy it, but if you are urging yourself, then put your eyes on it and keep an eye on the return period.

 

[BL218]

Face up Ideal-Scope results can give us a baseline idea of the light return and highlight any potential problem areas but, what it won't show, is the real world appearance...especially as the diamond is moving and tilting around like they tend to do when being worn.
An overly shallow pavilion angle will usually introduce over-obstruction, which is the darkening of the center that Karl stated.

The diamond is extremely steep and deep with a 64.4% depth. It was cut to retain as much carat weight as possible to hit that magic 2 carat mark.
Look at the diameter difference between the 2.0 VG and the 2.03 Ex = 7.86mm vs 8.15mm is a 0.29mm change in diameter, which is easily noticeable by most humans.
7.9mm is around the 1.90 carat mark for a well cut and proportioned RBC, so quite a lot of face-up size appearance is being lost with the 2.00 VG.

Now, if it were going to be purchased with the intent to recut to an antique round such as an OEC, then it's probably a good piece of rough.

However, diamonds can have that one in a million weirdo that plays by it's own rules, so maybe that 2.00 carat weight VG might be an exception to a set of very well defined and observed rules. I'm not urging you to buy it, but if you are urging yourself, then put your eyes on it and keep an eye on the return period.

Thanks for the detailed explanation. Do you think the Ex cut diamond is good? The proportion is like below.

Table: 56
Crown angle: 36.5
Pavilion angle: 40.8
Depth: 62.7

It also looks brighter than other EX or super ideal cut diamonds in the retailer’s 360 video.

 

[lovedogs]

Thanks for the detailed explanation. Do you think the Ex cut diamond is good? The proportion is like below.

Table: 56
Crown angle: 36.5
Pavilion angle: 40.8
Depth: 62.7

It also looks brighter than other EX or super ideal cut diamonds in the retailer’s 360 video.

You can't look at brightness that way due to differences in lighting. What other diamond are you comparing it to?

 

[DejaWiz]

Thanks for the detailed explanation. Do you think the Ex cut diamond is good? The proportion is like below.

Table: 56
Crown angle: 36.5
Pavilion angle: 40.8
Depth: 62.7

It also looks brighter than other EX or super ideal cut diamonds in the retailer’s 360 video.

You're very welcome!

No, that particular Ex with the 36.5 CA is showing indications of heightened leakages under the table, probably due to that steeper crown angle.
Can we help you find some better options to pick from?

 

[lovedogs]

You're very welcome!

No, that particular Ex with the 36.5 CA is showing indications of heightened leakages under the table, probably due to that steeper crown angle.
Can we help you find some better options to pick from?

Agreed

 

[BL218]

You're very welcome!

No, that particular Ex with the 36.5 CA is showing indications of heightened leakages under the table, probably due to that steeper crown angle.
Can we help you find some better options to pick from?

Thanks. Does that also mean the diamond would be less sparkle? Or its a separate matter?

 

[DejaWiz]

Thanks. Does that also mean the diamond would be less sparkle? Or its a separate matter?

Yes, the center of the diamond could have less brilliance and sparkle due to elevated light leakage.

 

[BL218]

Would additional cloud and surface grain in a VVS2 diamond affect its sparkle?

 

[lovedogs]

Would additional cloud and surface grain in a VVS2 diamond affect its sparkle?

Not in a VVS stone

 

[DejaWiz]

Would additional cloud and surface grain in a VVS2 diamond affect its sparkle?

Clouds, no.
Graining, not as simple to answer...other than maybe.

 

[Kim N]

Would you consider one of these options?

2.18 Carat round diamond

This 2.18 carat round diamond D color vvs2 clarity has Excellent proportions and a diamond grading report from GIA

www.jamesallen.com

2.03 Carat D-VS1 Excellent Cut Round Diamond

This 2.03 carat round diamond D color vs1 clarity has Excellent proportions and a diamond grading report from GIA

www.bluenile.com

2.13 Carat D-VS1 Excellent Cut Round Diamond

This 2.13 carat round diamond D color vs1 clarity has Excellent proportions and a diamond grading report from GIA

www.bluenile.com

 

[BL218]

The first 2 has quite a bit of comments including graining. Would that affect the light performance? Which one you think would have the best light performance?

How about this one below? It looks so crispy.

https://www.jamesallen.com/loose-diamonds/round-cut/2.03-carat-d-color-vs1-clarity-excellent-cut-sku-20647776?uniqueID=jhzemyla3_21115807

 

[Kim N]

The first 2 has quite a bit of comments including graining. Would that affect the light performance? Which one you think would have the best light performance?

How about this one below? It looks so crispy.

https://www.jamesallen.com/loose-diamonds/round-cut/2.03-carat-d-color-vs1-clarity-excellent-cut-sku-20647776?uniqueID=jhzemyla3_21115807

I don't think surface graining would affect performance in the first one, especially with it being a VVS2. I like the first one best.

The one you just posted has poor cut precision and symmetry.

 

[BL218]

I don't think surface graining would affect performance in the first one, especially with it being a VVS2. I like the first one best.

The one you just posted has poor cut precision and symmetry.

I see. The one i posted just looks so bright in the video so I wanna see if it is accurately reflecting the light performance. Thanks.

 

[lovedogs]

I see. The one i posted just looks so bright in the video so I wanna see if it is accurately reflecting the light performance. Thanks.

It's just lighting. The one you posted won't perform well in real life

 

[lovedogs]

Would you consider one of these options?

2.18 Carat round diamond

This 2.18 carat round diamond D color vvs2 clarity has Excellent proportions and a diamond grading report from GIA

www.jamesallen.com

2.03 Carat D-VS1 Excellent Cut Round Diamond

This 2.03 carat round diamond D color vs1 clarity has Excellent proportions and a diamond grading report from GIA

www.bluenile.com

2.13 Carat D-VS1 Excellent Cut Round Diamond

This 2.13 carat round diamond D color vs1 clarity has Excellent proportions and a diamond grading report from GIA

www.bluenile.com

All of these are better options

 

[BL218]

How about this one here? Seems to have good fire. Is it also just the lighting?

2.01 Carat round diamond

This 2.01 carat round diamond D color vvs2 clarity has Excellent proportions and a diamond grading report from GIA

www.jamesallen.com

 

[lovedogs]

The ones suggested above are better. Do you not like them?

 

[BL218]

Thanks. Just wanna do more research and learn about the selection criteria first. So keep checking on different diamonds and compare.

 

[BL218]

The ones suggested above are better. Do you not like them?

They look duller in the video but like you said it could be because of the lighting. So I m just keep comparing the spec of different diamonds and see if there are any actual correlation with the brightness showing in videos.

 

[Kim N]

They look duller in the video but like you said it could be because of the lighting. So I m just keep comparing the spec of different diamonds and see if there are any actual correlation with the brightness showing in videos.

The photography set-up varies for each diamond, so the brightness or fire you see in the videos can't really be used to compare them to each other. JA would have to create a single video with the diamonds you're considering for a fair comparison, but I'm pretty sure this isn't a service they offer.

 

[BL218]

Also wonder would cloud or additional cloud make the diamond look milky/hazy? Would faint fluorescent affect light performance much or make the diamond look milky?