Is this an excellent cut diamond?

[mommylawyer]

I am searching for a round brilliant lab diamond with an ideal or excellent cut. I've read that IGI ideal isn't the same as GIA excellent. I found a diamond that is an IGI ideal cut, but I can't figure out how this would rate under GIA. Here are the numbers. Any help would be appreciated.

HCA 0.9
Polish & Symmetry- Excellent
Table Size- 55%
Crown Height - Angle: 15% - 33.8 degrees
Pavilion Depth - Angle: 42% - 40.2 degrees
Total Depth- 60.6%

 

[anangel]

Follow the same guidelines for cut as you would a mined diamond. Their make up is the same, so there is no difference in the “ideal” angles.
I think the angles you’re asking about are a bit shallow for both crown and pavilion, but I tend to hold on the the much tighter, older ideal PS standards when shopping online. I’m not suggesting those will be the only angles with an excellent cut, but for a layman (Or woman) who is sorting through 100s of certs online, it does narrow down the results.

 

[mommylawyer]

Follow the same guidelines for cut as you would a mined diamond. Their make up is the same, so there is no difference in the “ideal” angles.
I think the angles you’re asking about are a bit shallow for both crown and pavilion, but I tend to hold on the the much tighter, older ideal PS standards when shopping online. I’m not suggesting those will be the only angles with an excellent cut, but for a layman (Or woman) who is sorting through 100s of certs online, it does narrow down the results.

Thank you.

 

[anangel]

Here are the guidelines I was referring to. Again, not saying that there are no beautiful diamonds outside of this range but these diamonds tend to score a 2 or under in the HCA:

Table : 54 - 58
Depth : 60 - 62.3
Crown : 34 - 35
Pavillion: 40.6 - 40.9

Note.... with a shallow Crown Angle like 34 you want to pair that with a Pavillion Angle like 40.8 to 40.9 and vice versa a Crown with 35 you pair that with a Pavillion of 40.6
These angles are complimentary.

 

[mommylawyer]

Here are the guidelines I was referring to. Again, not saying that there are no beautiful diamonds outside of this range but these diamonds tend to score a 2 or under in the HCA:

Table : 54 - 58
Depth : 60 - 62.3
Crown : 34 - 35
Pavillion: 40.6 - 40.9

Note.... with a shallow Crown Angle like 34 you want to pair that with a Pavillion Angle like 40.8 to 40.9 and vice versa a Crown with 35 you pair that with a Pavillion of 40.6
These angles are complimentary.

Thanks, this is very helpful!

 

[anangel]

Another resource; I believe this was the AGS grading chart. Based off the angles you provided, it looks like it’d be an AGS good or very good

 

[mommylawyer]

Another resource; I believe this was the AGS grading chart. Based off the angles you provided, it looks like it’d be an AGS good or very good

This is a great resource. Thanks so much for your help. I really appreciate it.

I know this will sound crazy, but how bad is a Good or VG cut (for a pendant, not an e-ring)? It's very difficult for me to see light leakage on the videos, and I have watched so many videos in an attempt to understand cut quality. The person says, "as you can see, the diamond in the middle clearly has more sparkle and fire...." but they all look the same to me. Perhaps I'm not sparkle sensitive. I can clearly see differences in color between a J and a G, for example. But I can't perceive differences in cut quality.

I like this diamond in particular because it faces up larger than it's carat weight. I believe it's called a "spread" diamond. The articles I've seen online all talk about spread diamonds with poor cuts, but this one is good or VG. What would you expect from this kind of stone? Less white flashes, less colored flashes? Will it appear dull and lifeless? Because I want to wear it as a pendant, it's more important how other people will perceive the diamond than how I perceive it myself.

 

[nala]

@mommylawyer my new stone falls under very good according to this chart. I used to have one that fell
Under ideal and guess what? The difference in fire performance is prob like 20 percent less? Does that make sense? But bc my new stone is an E vs the I that I had, it picks up colors A lot more! It is always on by reflecting the environment more than my previous one. Also, I see a lot of bold white flashes which I don’t recall observing in my previous one! I was totally stunned by this. So all this to say that very good can actually be close enough!! Almost like if you were comparing color or clarity—the difference Imo is like difference in one color or clarity grade at the very top of the scale. Hope that helps.

 

[mommylawyer]

@mommylawyer my new stone falls under very good according to this chart. I used to have one that fell
Under ideal and guess what? The difference in fire performance is prob like 20 percent less? Does that make sense? But bc my new stone is an E vs the I that I had, it picks up colors A lot more! It is always on by reflecting the environment more than my previous one. Also, I see a lot of bold white flashes which I don’t recall observing in my previous one! I was totally stunned by this. So all this to say that very good can actually be close enough!! Almost like if you were comparing color or clarity—the difference Imo is like difference in one color or clarity grade at the very top of the scale. Hope that helps.

Thank you very much for this great explanation!! This is really helpful. I know that a picture is worth a thousand words. But, for me, this thread has been worth a thousand videos!