Thoughts/Criticisms of this Diamond?

[abs100]

Hello - this is my first post on this forum and I have to say what a terrific site! I am so happy to have found this resource! I am seeking some help as I search for a diamond for an engagement ring. At the moment I have the diamond described below on hold and I am looking for some feedback/comments from the experts here before I buy. I am primarily focusing on size and cut while compromising on color/clarity although "eye clean" close up is critical to me and I want to stay in the colorless range. The vendor states that this stone is eye clean and looks bright and white when face up. I have also attached the Ideal Scope image to this message.

One thing which confuses me about this stone is that the HCA score is calculated as 2.2 with "very good" ratings for all four parameters even though this is an AGS Ideal 0 - I do not know what to think of that?

Thank you very much in advance!

Andrew

http://www.jamesallen.com/diamond.asp?find=1&cid=130&item=1077207

Shape: Round
Carat Weight: 1.67ct
Color: AGS 3.0 (J)
Clarity: AGS 5 (SI1)
AGS Cut Grade: Ideal 0
AGS Light Performance: Ideal
Polish: Ideal
Symmetry: Ideal
Fluorescence: Negligible
In House: Yes
Width: 7.60mm
Length: 7.56mm
Depth: 4.74mm
Table Percentage: 55.0%
Depth Percentage: 62.5%
Crown Angle : 35.1°
Crown Depth: 15.8%
Pavilion Angle : 40.9°
Pavilion Depth: 43.1%
Girdle: 1.3%

 

[chrono]

I am wondering if this is one of the stones that is making Gary think about revising the HCA to include stones up to 2.5 or something like that? The Idealscope looks really nice, and it is also falls into the AGS0 (just on the very edge of AGS0 rating)parameters. This stone looks like a very good buy.

 

[Ellen]

Chrono, I agree. I would imagine it''s the higher crown with the relatively deep pavillion that''s doing it.

The IS looks great. Should be pretty! And a nice size too.

 

[Skippy123]

looks nice from the picture!

 

[Ellen]

I fiddled out of curiosity.

abs, if you change only the CA to 35, you get a 2. If you change it to 34.9, it becomes a 1.9.

 

[abs100]

How interesting. So it would seem that the CA is the limiting factor here. Hmmm . . . I wonder if the cutter was trying to optimize for weight instead of for total light performance? I am not an expert but I am guessing it wouldn''t have been that hard to adjust that angle downward . . .

 

[JohnQuixote]

Date: 10/10/2007 1:15:28 PM
Author: abs100
How interesting. So it would seem that the CA is the limiting factor here. Hmmm . . . I wonder if the cutter was trying to optimize for weight instead of for total light performance? I am not an expert but I am guessing it wouldn't have been that hard to adjust that angle downward . . .

No, this diamond came out well. Remember that when you're talking about the hardest material on earth and objects that are 8mm across 'adjusting the angle downward' in the polishing process is not so simple, nor is it in any way simple to hit the 'AGS0 bullseye' - as this diamond has.

Some perspective: Stand in your living room and face forward. Then face to your right. You have just swept across 90 degrees to make that turn. Now remember that the difference discussed here (between 35.1 and 34.9) is two-tenths of one single degree. This diamond came out as planned and it earned the AGS0. Sure, if they had planned and executed at 34.X it would have fallen inside a certain numerical Tolkowsky "sweet spot" but there is going to be no visible difference in two-tenths of a degree in crown angle (pavilion angle is a bit more critical)...especially when we keep in mind that the crown angle is the average of eight numbers.

 

[Ellen]

Date: 10/10/2007 1:15:28 PM
Author: abs100
How interesting. So it would seem that the CA is the limiting factor here. Hmmm . . . I wonder if the cutter was trying to optimize for weight instead of for total light performance? I am not an expert but I am guessing it wouldn''t have been that hard to adjust that angle downward . . .

No, you could change the PA only as well and get different results.

But, the IS image trumps the HCA, so no worries. Remember, the IS image is an actual pic of the actual diamond, the HCA hasn''t seen it.

As Chrono was saying, Gary has considered changing things a bit. The HCA prefers shallower numbers, but that dooesn''t mean stones with steeper numbers can''t look good, they can. And you''ve got one there.

 

[abs100]

I really appreciate the feedback - this is very helpful - especially for a novice like me! From my reading I had realized that the IS image would provide insight into the accuracy/symmetry of the cuts yet I did not realize that the IS image also can help determine the degree to which the various (crown/pavilion) angles were optimized to yield good light characteristics.

Sounds as though the consensus is that this stone is a good overall option. My sense is that the price for this stone is fair - any perspective in that regard - good deal/bad deal?

Thanks again!

Andrew

 

[:)]

Date: 10/10/2007 12:03:21 PM
Author:abs100
Hello - this is my first post on this forum and I have to say what a terrific site! I am so happy to have found this resource! I am seeking some help as I search for a diamond for an engagement ring. At the moment I have the diamond described below on hold and I am looking for some feedback/comments from the experts here before I buy. I am primarily focusing on size and cut while compromising on color/clarity although ''eye clean'' close up is critical to me and I want to stay in the colorless range. The vendor states that this stone is eye clean and looks bright and white when face up. I have also attached the Ideal Scope image to this message.

One thing which confuses me about this stone is that the HCA score is calculated as 2.2 with ''very good'' ratings for all four parameters even though this is an AGS Ideal 0 - I do not know what to think of that?

Thank you very much in advance!

Andrew

http://www.jamesallen.com/diamond.asp?find=1&cid=130&item=1077207

Shape: Round
Carat Weight: 1.67ct
Color: AGS 3.0 (J)
Clarity: AGS 5 (SI1)
AGS Cut Grade: Ideal 0
AGS Light Performance: Ideal
Polish: Ideal
Symmetry: Ideal
Fluorescence: Negligible
In House: Yes
Width: 7.60mm
Length: 7.56mm
Depth: 4.74mm
Table Percentage: 55.0%
Depth Percentage: 62.5%
Crown Angle : 35.1°
Crown Depth: 15.8%
Pavilion Angle : 40.9°
Pavilion Depth: 43.1%
Girdle: 1.3%

Have you seen J''s in person? J is not colorless if you truly want to stay in colorless by strict definition (which is DEF), are you certain you want colorless, or is some warmth okay (would be most evident from the sides)? How color sensitive are you/your mate?

 

[abs100]

This my "newbieness" showing! I really meant to say near colorless. I have seen J color stones and I am not overly concerned with that aspect as neither I nor my soon to be fiance are too sensitive to it. Thanks for point that out though - as you can tell - I do need help!

 

[Ellen]

Date: 10/10/2007 2:43:49 PM
Author: abs100
I really appreciate the feedback - this is very helpful - especially for a novice like me! From my reading I had realized that the IS image would provide insight into the accuracy/symmetry of the cuts yet I did not realize that the IS image also can help determine the degree to which the various (crown/pavilion) angles were optimized to yield good light characteristics.

Sounds as though the consensus is that this stone is a good overall option. My sense is that the price for this stone is fair - any perspective in that regard - good deal/bad deal?

Thanks again!

Andrew

JA has some of the best pricing, so yes, I think it''s a good deal.