wow!! is this a good diamond

[Kirbycario]

https://www.jamesallen.com/loose-di...d-color-vs2-clarity-excellent-cut-sku-7823351

D VS2 0.77 carat
$2870
seems rather good value for its price, eyeclean?
but strong blue fluorescence on D colour - but it doesnt seem milky/hazy?

 

[sledge]

Crown angle is too high at 36.5. But it does have a shallow & complimentary pavilion at 40.6. Depth is border line but acceptable. The arrows have a nice crisp pattern in the video.

We normally recommend staying with a crown angle in the range of 34-35. Sometimes you see people push to the outer limits of 35.5 or 36, when paired with a 40.6 angle.

Entering the data into the HCA, you can see it gets a 2.2 score. Normally you want to be at a 2 or less; however, when you have very good hearts & arrow (H&A) patterning you can sometimes push up to the 2.5 mark. Again, the arrows look pretty nice in the video but we don't have a hearts image available to review.

On the HCA, for maximum performance, you want the light return, fire & scintillation to all be "excellent". This particular stone is predicted to only score very good, which is one click lower. Not surprising when you expand the HCA and look at the graphical plots for GIA and AGS potential cut grades. It's in a border line position.




This border line prediction is also confirmed in my much less fancy or sophisticated spreadsheet based on 2009 AGS proportions charts. It lands firmly in the middle of ideal, excellent and very good.

To make further determinations about the stone, you'd want to request an idealscope (IS) image from JA to give us some additional data to go on.

 

[mwilliamanderson]

They don’t photograph diamonds under UV light so you won’t see the fluorescence until you get it outside or under artificial uv light. The crown is overly steep so ask for IS/ASET images. There may be leakage.

Most advice I’ve seen on Pricescope
says be careful with SBF on high color stones.

 

[sledge]

Good point by @mwilliamanderson about the SBF. I got caught up in the other and failed to comment on that aspect. SBF is not desirable in higher colored stones, especially a D. Consequently, the stone will be monetarily discounted.

Fluor isn't always bad. In many cases, it's not a problem. But the higher the levels, the more probable. Strong and very strong are the two highest concentrations.

I was helping another person on here the other day with a stone from JA that had MBF. The videos did not look hazy/milky but when JA brought the stone in the gemologist reviewed it (upon request) and confirmed it had a slight haze to it.

So anytime you are dealing with fluor, it's wise to have it checked out to ensure there are no problems.

 

[headlight]

Crown angle is too high at 36.5. But it does have a shallow & complimentary pavilion at 40.6. Depth is border line but acceptable. The arrows have a nice crisp pattern in the video.

We normally recommend staying with a crown angle in the range of 34-35. Sometimes you see people push to the outer limits of 35.5 or 36, when paired with a 40.6 angle.

Entering the data into the HCA, you can see it gets a 2.2 score. Normally you want to be at a 2 or less; however, when you have very good hearts & arrow (H&A) patterning you can sometimes push up to the 2.5 mark. Again, the arrows look pretty nice in the video but we don't have a hearts image available to review.

On the HCA, for maximum performance, you want the light return, fire & scintillation to all be "excellent". This particular stone is predicted to only score very good, which is one click lower. Not surprising when you expand the HCA and look at the graphical plots for GIA and AGS potential cut grades. It's in a border line position.




This border line prediction is also confirmed in my much less fancy or sophisticated spreadsheet based on 2009 AGS proportions charts. It lands firmly in the middle of ideal, excellent and very good.

To make further determinations about the stone, you'd want to request an idealscope (IS) image from JA to give us some additional data to go on.

So I thought that you don’t get extra credit just because you get excellent in a category... that it’s just about the total score. I am constantly questioning it as why else have the distinction so when I saw what you posted it opened up that for me again. So is there just a difference in philosophy here amongst everyone on this? Thx!

 

[lovedogs]

I'm not a huge fan of this because of the high crown angle.

 

[headlight]

I think the strong blue Fl is represented in the price as this would be a devaluation of sorts for a D perfect GIA grade.

 

[mwilliamanderson]

So I thought that you don’t get extra credit just because you get excellent in a category... that it’s just about the total score. I am constantly questioning it as why else have the distinction so when I saw what you posted it opened up that for me again. So is there just a difference in philosophy here amongst everyone on this? Thx!

In my opinion I want:

Light Return: Excellent
Fire: Excellent
Scintillation: Excellent
Spread: Very Good

Not sure that I’ll get extra credit but some measure of peace of mind knowing I did the best I could.

 

[MMtwo]

This border line prediction is also confirmed in my much less fancy or sophisticated spreadsheet based on 2009 AGS proportions charts. It lands firmly in the middle of ideal, excellent and very good.

To make further determinations about the stone, you'd want to request an idealscope (IS) image from JA to give us some additional data to go on.

OOooooh I love your spreadsheet!

 

[sledge]

So I thought that you don’t get extra credit just because you get excellent in a category... that it’s just about the total score. I am constantly questioning it as why else have the distinction so when I saw what you posted it opened up that for me again. So is there just a difference in philosophy here amongst everyone on this? Thx!

This is how I understand HCA:

• Scores 0-1 are preferred for earrings & pendants.
• Scores 1-2 are preferred for e-rings.
• Scores 0-2 are preferred and what is recommended by most here.
• As shown in the screen cap above, scores up to 2.5 can actually be considered but you need to verify the cut quality so H&A imaging is recommended.
• A 1.3 has no different value than a 1.5. However, a 0.7 may have a different value than a 1.3 because of the earring/pendant and e-ring recommendation.
• The values for fire, scintillation and light return are affected by the proportions entered and how the HCA calculates the data. Obviously a higher grade indicates a stone of higher performance. Just as the new size functions tells you if a stone measures average, large, small, etc.
• The HCA is an approximation and not a guarantee. In fact, the values on the GIA/AGS certs are rounded/averaged values. The HCA then makes it own assumptions using those cert values. So in a sense you get a few layers of approximations. At the end of the day, the HCA is a great rejection tool to narrow your list of potential stones that show reasonable promise of complimentary proportions and performance, but in no way provides assurance of a great stone.
• Any time you run the HCA, it states to confirm performance with an IS image (also, an ASET would substitute for the IS image).