what is Type IaAB diamond on EGL report?

[whitneyc]

What does type IaAb diamond on EGL report mean? I am looking at this diamond from ID Jewelry...

Type of certificate: Certificate
Important Limitations:
Online Verification data is not an EGL gemological report of any kind. It is only intended to confirm the issuance of a gemological report by EGL International.
Report Number: EGL3026120014
Date: 09/06/2010
GRADING RESULTS
Cristal Type: Type IaAB
Shape and Cut: Round Brilliant
Carat weight: 1.72 Ct.
Color Grade: D
Clarity Grade: SI3

ADDITIONAL GRADING INFORMATION
Measurements: 7.84 - 7.80 x 4.66
Polish: Excellent
Symmetry: Excellent
Fluorescence: None
Total Depth: 59.6 %
Table Width: 56 %
Crown Height: 15 %
Pavillon Depth: 42 %
Girdle Thickness: Thin, Faceted

COMMENTS

- 8 HEARTS & 8 ARROWS - This Diamond was polished
utilizing superior precision & craftmanship, its
exquisite proportions generate the appearance of
8 Hearts & 8 Arrows, when viewed at the correct
angle & under the proper lighting conditions.
- 'Excellent Ideal Cut'.




THANK YOU IN ADVANCE!

 

[Garry H (Cut Nut)]

What does type IaAb diamond on EGL report mean? I am looking at this diamond from ID Jewelry...

Type of certificate: Certificate
Important Limitations:
Online Verification data is not an EGL gemological report of any kind. It is only intended to confirm the issuance of a gemological report by EGL International.
Report Number: EGL3026120014
Date: 09/06/2010
GRADING RESULTS
Cristal Type: Type IaAB
Shape and Cut: Round Brilliant
Carat weight: 1.72 Ct.
Color Grade: D
Clarity Grade: SI3

ADDITIONAL GRADING INFORMATION
Measurements: 7.84 - 7.80 x 4.66
Polish: Excellent
Symmetry: Excellent
Fluorescence: None
Total Depth: 59.6 %
Table Width: 56 %
Crown Height: 15 %
Pavillon Depth: 42 %
Girdle Thickness: Thin, Faceted

COMMENTS

- 8 HEARTS & 8 ARROWS - This Diamond was polished
utilizing superior precision & craftmanship, its
exquisite proportions generate the appearance of
8 Hearts & 8 Arrows, when viewed at the correct
angle & under the proper lighting conditions.
- 'Excellent Ideal Cut'.




THANK YOU IN ADVANCE!

It seems like jargon for jargon's sake. There have been reports that Type IaAB can be treated from yellowish to colourless, but to my knowledge there are no commercial applications.

If the stone was fancy yellow or greenish it would probably be high pressure and heat treated, but at a high color - D ( or even if the EGL D might be E or F from other labs) then you have nothing to worry about.
Type IaAB means it has some nitrogen floating about in a few different states - but if the stone had been treated it would go a bright yellowish colour. I have some
EGL SI3 = I1 so please take that into account too on pricing.

 

[whitneyc]

What does type IaAb diamond on EGL report mean? I am looking at this diamond from ID Jewelry...

Type of certificate: Certificate
Important Limitations:
Online Verification data is not an EGL gemological report of any kind. It is only intended to confirm the issuance of a gemological report by EGL International.
Report Number: EGL3026120014
Date: 09/06/2010
GRADING RESULTS
Cristal Type: Type IaAB
Shape and Cut: Round Brilliant
Carat weight: 1.72 Ct.
Color Grade: D
Clarity Grade: SI3

ADDITIONAL GRADING INFORMATION
Measurements: 7.84 - 7.80 x 4.66
Polish: Excellent
Symmetry: Excellent
Fluorescence: None
Total Depth: 59.6 %
Table Width: 56 %
Crown Height: 15 %
Pavillon Depth: 42 %
Girdle Thickness: Thin, Faceted

COMMENTS

- 8 HEARTS & 8 ARROWS - This Diamond was polished
utilizing superior precision & craftmanship, its
exquisite proportions generate the appearance of
8 Hearts & 8 Arrows, when viewed at the correct
angle & under the proper lighting conditions.
- 'Excellent Ideal Cut'.




THANK YOU IN ADVANCE!

It seems like jargon for jargon's sake. There have been reports that Type IaAB can be treated from yellowish to colourless, but to my knowledge there are no commercial applications.

If the stone was fancy yellow or greenish it would probably be high pressure and heat treated, but at a high color - D ( or even if the EGL D might be E or F from other labs) then you have nothing to worry about.
Type IaAB means it has some nitrogen floating about in a few different states - but if the stone had been treated it would go a bright yellowish colour. I have some
EGL SI3 = I1 so please take that into account too on pricing.

thank you, the price seems to be right, almost "too good to be true". Here is a copy of the certification. Any help on this stone would be great I am pretty anxious on hearing back from the jeweler..

 

[stone-cold11]

On the shallow side, might have obstruction issue. IdJewelry can give get you an idealscope and H&A image for that stone to verify.

 

[whitneyc]

I have requested an image.. i am (im)patiently waiting.. Here is the HCA while I wait to hear back from them. I understand EGL is a little lenient on their grading, even so, that wouldn't change the HCA much would it?

 

[stone-cold11]

You see the percentage crown and pavilion height, that is in 1% step size? 1 percent change in pavilion depth means an angle change of about 0.7 degrees and see how much that translate to on the HCA?

Also read the warning about HCA. http://www.pricescope.com/wiki/diamonds/holloway-cut-advisor

The stone, assuming not rounding error, is in the pendant stone range, meaning it will probably have obstruction issue if you are looking at it too close.

 

[whitneyc]

You see the percentage crown and pavilion height, that is in 1% step size? 1 percent change in pavilion depth means an angle change of about 0.7 degrees and see how much that translate to on the HCA?

yes, I do, one little smidge could mean a lot, hopefully (fingers crossed) there aren't many "smidges"

 

[Tom Gelb]

Hello,

Just to answer the question. The vast majority of diamonds are type 1a, which means that there is detectable nitrogen in the infrared spectrum. This nitrogen can be aggregated in many forms, but the most common are A and B aggregates. Thus type 1aAB means that the diamond has nitrogen and it is aggregated in some common forms. My understanding is that EGL and a few other labs run all diamonds through their FTIR spectrometer. I guess one might as well put it on a report since they did the work anyway.

Good luck,