HPHT type ll and HPHT GIA diamond, which is better? GIA has no tye ll

[Jessica - V]

Wouldn't IGI colors usually be one level lower (e.g. color F would be color G or H) ? I bought 4 carats GIA lab , I am thinking should I buy IGI Tye ll ? Ritani is in short supply , and the price seems to be increasing . I don't see any 3 carat or more pear diamonds

 

[momofive]

Also, keep an eye on Parksantiquelab on IG. They sometimes put up beautiful fancy cuts, but they go quickly.

And, from all my reading on PS, IGI, in the past tended to grade higher than GIA, but I think some people have been saying IGI is getting tighter with their color grades. But that's not definitive, so really not a good answer for you! Sorry!

 

[Kim N]

It's not always true that GIA is stricter than IGI. I would have no concern with IGI for a lab diamond.

While not a large sample size, Ada Diamonds dual-graded a number of stones with GIA and IGI/GCAL.

GIA Graded Lab Diamonds: First Results!

Last week I shared the results of AGS’s return to grading lab diamonds, as part of our involvement with the AGS lab diamond pilot program. We are also one of the first to receive full-fidelity GIA grading reports, with 17 diamonds sent to GIA for secondary grading. The results? Unsurprising...

www.pricescope.com

 

[DejaWiz]

IGI seems to only report Type II for HPHT instead of breaking in down further into either IIa or IIb.

GIA usually doesn't even give diamond Type or Subtype.

Regardless of the grading lab, you'll still need to check for blue nuance (Type IIb), as even GIA will grade HPHT diamonds in the D-F colorless scale that have blue nuance, same as IGI.

If no blue nuance, then it's almost always Type IIa.

 

[Jessica - V]

IGI dường như chỉ báo cáo Loại II cho HPHT thay vì phân tích sâu hơn thành IIa hoặc IIb.

GIA thường thậm chí không đưa ra Loại kim cương hoặc Loại phụ.

Bất kể phòng thí nghiệm phân loại là gì, bạn vẫn cần kiểm tra sắc thái xanh lam (Loại IIb), vì ngay cả GIA cũng sẽ phân loại kim cương HPHT theo thang không màu DF có sắc thái xanh lam, giống như IGI.

Nếu không có sắc xanh lam, thì đó hầu như luôn là Loại IIa.

@ KIM N , @ Dẹawiz , @ momofive Thank you, help me gain more knowledge about diamond lab

 

[Garry H (Cut Nut)]

It's not always true that GIA is stricter than IGI. I would have no concern with IGI for a lab diamond.

While not a large sample size, Ada Diamonds dual-graded a number of stones with GIA and IGI/GCAL.

GIA Graded Lab Diamonds: First Results!

Last week I shared the results of AGS’s return to grading lab diamonds, as part of our involvement with the AGS lab diamond pilot program. We are also one of the first to receive full-fidelity GIA grading reports, with 17 diamonds sent to GIA for secondary grading. The results? Unsurprising...

www.pricescope.com

John Pollard has been saying for some time that IGI is stricter on color for grown diamonds. And that survey reflects it.
GIA it appears were worried about loosing business to IGI - the leader in grown diamond grading business. Dropping treatment from GIA reports makes sellers happy as it puts a fear into people.
A recent webinar with ADA and GIA put forward an idea that treatment anneals and reduces breakages. That may well be so but I never read any empirical R&D to prove that.