IGI HPHT H&A vs AGSL CVD AGS 0

[0-0-0]

Found a matching pair of IGI graded HPHT H&A cuts to compare with an AGSL graded CVD AGS 0 cut. All are eye clean D color VS clarity. No visible fluorescence or phosphorescence.

Carat Weight	1.76	1.74	1.312
Measurements	7.75 - 7.78 x 4.76	7.73 - 7.77 x 4.74	7.04 - 7.06 x 4.31
Depth	61.2%	61.1%	61.1%
Table	56.5%	56%	56.9%
Crown Angle	34.1	34	34.6
Crown Height	15%	15%	14.9%
Pavilion Angle	40.7	40.7	40.7
Pavilion Depth	43%	43%	43.0%
Star Facets			51
Lower Girdle			76

1.76

Loupe360

loupe360.com

1.74

Loupe360

loupe360.com

1.312

AGS Laboratories

agslab.com

1.74 vs 1.76

https://imgur.com/a/reoU0nO

1.312 vs 1.74

https://imgur.com/a/JRGoUG8

https://imgur.com/a/FSRTePD

My observations:

• Minimal differences between HPHT and CVD in color and transparency
• The paddling visible in the ASET images is not noticeable in person
• Minimal differences between the 1.76 and 1.74 in person
• Easier to take images of the 1.312 with crisper patterning
• The 1.312 looks more lively in motion than the IGI pair

The IGI pair faces up 20% bigger, yet the 1.312 is still more eye catching in motion in hand. The facets in the 1.312 switches on/off at a faster rate. On ears at farther distances, the difference in size becomes more apparent than the difference in cut quality.

There’s a 3x price difference between the cheapest and the priciest IGI H&A cuts with similar carat weight, color, and clarity. This IGI pair is in the lower end of the price spectrum. I didn’t find any issues with the material and I certainly wouldn’t pay up to 3x as much for a marginal improvement in cut.

For a ring, I would consider going down in size for better cut quality for the same price. I didn’t expect to find that this marginal improvement in cut quality is enough to level the playing field against another round that faces up 20% bigger. This comparison changed my mind.

 

[Kim N]

Thank you for sharing your detailed analysis!

 

[Garry H (Cut Nut)]

0-0-0 you are a research scientist?
Well done!

 

[DejaWiz]

This is such a fantastic analysis and comparison, which attunes nicely with the recent PS blog sit-down with John Pollard about IGI having made great strides to garner a more accepted reputation in the industry.
Thank you for taking the time to do this for everyone here, 0-0-0!

 

[0-0-0]

Bonus round!

Scored a IGI graded faint blue G color HPHT for a bargain price. No H&A designation. Crown angle is outside the PS recommended safe range. Eye clean VS2 with no visible fluorescence or phosphorescence.

Carat Weight	2.62	1.74	1.312
Measurements	8.88 - 8.92 x 5.43	7.73 - 7.77 x 4.74	7.04 - 7.06 x 4.31
Depth	61%	61.1%	61.1%
Table	55.5%	56%	56.9%
Crown Angle	33	34	34.6
Crown Height	14.5%	15%	14.9%
Pavilion Angle	40.8	40.7	40.7
Pavilion Depth	43%	43%	43.0%
Star Facets			51
Lower Girdle			76

2.62

Loupe360

loupe360.com

1.312 vs 2.62

https://imgur.com/a/JfROguO

My observations:

• Tiniest hint of blue in the 2.62 only in some lighting and at certain angles, otherwise almost as colorless as the others
• The paddling and increased amount of blue/obstruction in the ASET is only noticeable in person at a distance closer than 6 inches
• The 2.62 has crisper patterning and looks more lively in motion than the IGI H&A pair

The 2.62 looks as lively in motion as the 1.312 in person, but it’s hard to say whether it’s due to the cut precision being as good or the substantial increase in the size and number of visible virtual facets. The 60% increase in face up size really stands out. Unfortunately I don’t have a loose diamond of similar size to compare with in person.

The IGI H&A pair doesn’t look as lively in motion as either the 2.62 or the 1.312, so I didn’t bother taking any additional comparison videos with them.

 

[lovedogs]

the 2.62 is amazing!!!!

 

[0-0-0]

Give me all your faint blues if they all look like this!

 

[0-0-0]

2 more IGI HPHT H&A to add to the comparison, 2.57 E and 4.12 F both with blue nuance. The faint blue G convinced us to take the discount that comes with blue nuance whenever possible. Both are eye clean VS1 with no visible fluorescence or phosphorescence.

Carat Weight	2.57	4.12	2.62
Measurements	8.80 - 8.82 x 5.40	10.37 - 10.42 x 6.26	8.88 - 8.92 x 5.43
Depth	61.3%	60.3%	61%
Table	57%	58%	55.5%
Crown Angle	34.3	34	33
Crown Height	15%	14.5%	14.5%
Pavilion Angle	40.7	40.7	40.8
Pavilion Depth	43%	43%	43%

2.57 E

Loupe360

loupe360.com

4.12 F

Loupe360

loupe360.com

2.57 E vs 4.12 F vs 2.62 faint blue G on white paper

https://imgur.com/a/leZN22V

4.12 F vs 2.57 E

https://imgur.com/a/AGrwIps

2.57 E vs 2.62 faint blue G

https://imgur.com/a/sYV0KO5

My observations:

• Minimal blue tint in the 2.57 E compared with the 4.12 F and 2.62 faint blue G
• The blue tint is more apparent in the 4.12 F than in the 2.62 faint blue G
• All look colorless face up and as lively in motion as the 1.312 D
• The 4.12 F sits a bit high in the holding plate, so the ASET image looks a bit off and the increased amount of obstruction is not visible in person

Vendor videos are pretty accurate for color for the 2.57 E, 4.12 F, and 2.62 G. Some vendor videos have backgrounds that look more grey and are not as helpful in assessing color.

The ASET image of the 1.312 D looks the cleanest and most crisp in comparison. Yet in person, it is really hard to spot any difference in cut quality between the 1.312 D, the 2.57 E, and the 4.12 F. The substantial increase in the size and number of visible virtual facets likely masks any difference in cut precision.

The visible difference in cut quality between the 2.62 G and the 2.57 E is also quite small in person given the differences in reported numbers and H&A designation. Other than slightly more obstruction up close the 2.62 G performs pretty much identically.

 

[DejaWiz]

2 more IGI HPHT H&A to add to the comparison, 2.57 E and 4.12 F both with blue nuance. The faint blue G convinced us to take the discount that comes with blue nuance whenever possible. Both are eye clean VS1 with no visible fluorescence or phosphorescence.

Carat Weight	2.57	4.12	2.62
Measurements	8.80 - 8.82 x 5.40	10.37 - 10.42 x 6.26	8.88 - 8.92 x 5.43
Depth	61.3%	60.3%	61%
Table	57%	58%	55.5%
Crown Angle	34.3	34	33
Crown Height	15%	14.5%	14.5%
Pavilion Angle	40.7	40.7	40.8
Pavilion Depth	43%	43%	43%

2.57 E

Loupe360

loupe360.com

4.12 F

Loupe360

loupe360.com

2.57 E vs 4.12 F vs 2.62 faint blue G on white paper

https://imgur.com/a/leZN22V

4.12 F vs 2.57 E

https://imgur.com/a/AGrwIps

2.57 E vs 2.62 faint blue G

https://imgur.com/a/sYV0KO5

My observations:

• Minimal blue tint in the 2.57 E compared with the 4.12 F and 2.62 faint blue G
• The blue tint is more apparent in the 4.12 F than in the 2.62 faint blue G
• All look colorless face up and as lively in motion as the 1.312 D
• The 4.12 F sits a bit high in the holding plate, so the ASET image looks a bit off and the increased amount of obstruction is not visible in person

Vendor videos are pretty accurate for color for the 2.57 E, 4.12 F, and 2.62 G. Some vendor videos have backgrounds that look more grey and are not as helpful in assessing color.

The ASET image of the 1.312 D looks the cleanest and most crisp in comparison. Yet in person, it is really hard to spot any difference in cut quality between the 1.312 D, the 2.57 E, and the 4.12 F. The substantial increase in the size and number of visible virtual facets likely masks any difference in cut precision.

The visible difference in cut quality between the 2.62 G and the 2.57 E is also quite small in person given the differences in reported numbers and H&A designation. Other than slightly more obstruction up close the 2.62 G performs pretty much identically.

I think that they're ALL wonderful contenders...which one has your target lock?

 

[0-0-0]

Size matters

They are all for different projects we have in mind. May not be getting around to setting them soon, but got them at price points that are really hard to resist.

Hopefully the comparisons are helpful, especially for others considering HPHT with blue nuance. The blue tints can be extremely minor and the discounts can be huge.

 

[lovedogs]

I love all of them

 

[0-0-0]

Double checked the lab diamonds for fluorescence/phosphorescence in a completely dark room, and the 2.57 and 4.12 actually have faint white phosphorescence. I just didn’t check them out in a room that was completely dark before. Apparently even sunlight is enough to activate the faint white phosphorescence, and it lasts quite a while. The phosphorescence in the 2.57 stays white until it fades, but the phosphorescence in the 4.12 turns more yellow as it fades. Really surprising and cool find. None of the other lab diamonds, not even the faint blue G, have any fluorescence/phosphorescence.

Diamonds were in sunlight before the start of the video. Video starts with led light on/off and then UV light on/off.

https://imgur.com/a/EDBb3MP

 

[0515vision]

Found a matching pair of IGI graded HPHT H&A cuts to compare with an AGSL graded CVD AGS 0 cut. All are eye clean D color VS clarity. No visible fluorescence or phosphorescence.

Carat Weight	1.76	1.74	1.312
Measurements	7.75 - 7.78 x 4.76	7.73 - 7.77 x 4.74	7.04 - 7.06 x 4.31
Depth	61.2%	61.1%	61.1%
Table	56.5%	56%	56.9%
Crown Angle	34.1	34	34.6
Crown Height	15%	15%	14.9%
Pavilion Angle	40.7	40.7	40.7
Pavilion Depth	43%	43%	43.0%
Star Facets			51
Lower Girdle			76

1.76

Loupe360

loupe360.com

1.74

Loupe360

loupe360.com

1.312

AGS Laboratories

agslab.com

1.74 vs 1.76

https://imgur.com/a/reoU0nO

1.312 vs 1.74

https://imgur.com/a/JRGoUG8

https://imgur.com/a/FSRTePD

My observations:

• Minimal differences between HPHT and CVD in color and transparency
• The paddling visible in the ASET images is not noticeable in person
• Minimal differences between the 1.76 and 1.74 in person
• Easier to take images of the 1.312 with crisper patterning
• The 1.312 looks more lively in motion than the IGI pair

The IGI pair faces up 20% bigger, yet the 1.312 is still more eye catching in motion in hand. The facets in the 1.312 switches on/off at a faster rate. On ears at farther distances, the difference in size becomes more apparent than the difference in cut quality.

There’s a 3x price difference between the cheapest and the priciest IGI H&A cuts with similar carat weight, color, and clarity. This IGI pair is in the lower end of the price spectrum. I didn’t find any issues with the material and I certainly wouldn’t pay up to 3x as much for a marginal improvement in cut.

Gosh I missed this last year (or more likely I was such a newbie that I couldn’t process all of this information). I have some questions and hope it’s OK to revive this thread.

@0-0-0, When you bought the 1.312, did you know you were buying a better cut quality? That is, was it branded as a precision cut? Or did you just happen to discover that once you received it in hand?

How much of the differences in light return from the IGI pair, and the 1.312 are from the differences in pavilion angle?

And forgive me, if you already answered this question, but is the fact that the 1.3 12 ASET so much crisper because of the quality of cut?

And are we pretty much at the mercy of our own personal home ASET imaging when trying to find better cut stones?

Also, you said, for earrings, size eventually trumps cut quality at a distance. What sort of distance did you mean? Like normal “standing in front of a person and chatting” distance or like “right in front of your face smell my breath“ distance?

Again, apologies for reviving an old thread if these have already been answered!

 

[0-0-0]

Good questions!

The 1.312 is not a branded cut. It’s one of the AGS graded labs I found and ordered from Ritani. The AGS report includes ASET and H&A images so I was reasonably certain that it is well cut.

The averaged pavilion angle as noted on the reports is the same 40.7 on the 1.312 and the 1.7 pair. Both AGS and IGI round angles to 0.1. I think the crisper patterning in the ASET and the more even looking hearts infer less variance/more precision in the non averaged angles. The crisper patterning matches the patterning of branded H&A cuts that I own.

I consider anything within arms reach (~2 feet) to be ring distance, and anything beyond that to be earring distance. So in my comparison, I find that the marginal improvement in cut precision in H&A rounds is more eye catching in motion than a ~20% increase in face up size at a distance of up to ~2 feet.

I compared them on ears at farther distances by putting them next to each other in the same gem box, holding the box next to my face, and looking in the bathroom mirror (~2-4 feet).

I think advanced imaging can help narrow down options for better cut stones, but at the end of the day I still have to see and compare the actual stones to see if the differences matter in person.

The cut on the 1.7 pair is perfectly acceptable, even for a ring, had I not had the better cut 1.312 as a point of comparison. Others may not find the cut differences to be as apparent and opt for bigger size.

 

[0515vision]

@0-0-0, thank you for such a thorough explanation!

It’s so helpful to take into account distance and purpose of a stone when evaluating cut. This is especially true when coupled with the drastic price differences between similar ct/color/clarity/cut diamonds.

Eventually, I want to add 1.5–2 carat stones to a current pair of 0.60 dangle earrings. Whiteflash has one 1.5 $2000 Precision Cut stone and a 1.5 $900 non-branded stone. Both had nearly identical cut specs. If I had the funds, I would buy them both and compare in person the way you have.

Your comparison may end up saving me a couple thousand dollars! Always appreciate your posts!

 

[0-0-0]

Glad it’s helpful! The substantial price gap at bigger sizes keeps me away from the branded lab cuts too! If you are going through WF I wonder if they'll offer photo/video comparisons between them to help your decision.

 

[Garry H (Cut Nut)]

One of the saddest things in our industry is the lack of all sorts of photos and information that are dumped by wholesalers once diamonds leave India (where 90% are cut and polished).
An Indian grower and cutter sent me a lait last week and there were ideal-scope ASET phots and videos on thousands of stones down to 1ct for $129!

 

[0515vision]

An Indian grower and cutter sent me a lait last week and there were ideal-scope ASET phots and videos on thousands of stones down to 1ct for $129!

Alex Park sold bundles of 1ct pears, emeralds and ovals for $220 each two weeks ago. If he's making a profit, then 1ct for $129 sounds about right.

 

[Garry H (Cut Nut)]

Alex Park sold bundles of 1ct pears, emeralds and ovals for $220 each two weeks ago. If he's making a profit, then 1ct for $129 sounds about right.

Yup, he would (or should) be getting them for less than the company that went to the bother of offering high quality service.
Another strange feature of LGD is that rounds are cheaper than most fancy shapes.
A lot more automation in polishing.