Trick Question

[antonia]

Further to my "knowledge is power" post....

We paid just over au$1,000 for an "excellent cut" diamond, i.e the highest cut grade (AGS Excellent).

We found an E SI1 1.186 stone (details also previous posted) with a big variance in the girdle so I asked to my jeweller whether in would rate an excellent cut because of this, and the crown angle wasn't so great either... anyway..
THE POINT IS

The stone is in Belgium so he didn't want to to send it to AGS but suggested IGI which I agreed. He said if it rated excellent in cut would I be happy. I said yes. BUT

IS AGS EXCELLENT CUT EQUIVALENT TO IGI EXCELLENT CUT?

I just noticed IGI have an ideal cut grading!!!! Or am I worrying about something totally insignificant?

ADDITIONALLY

he said he cannot provide me with an Idealscope image because the guy in Belgium has never heard of that before and doesnt know what it is!??

THANK YOU ALL!

 

[pqcollectibles]

IGI is fast and cheap. That's probably why your jeweler wanted to use them. It's a recognized name world wide so why would any consumer question the verification. The IGI Certs I've seen do not provide angles information.

On the Ideal Scope image,..... Have your jeweler ask the wholesaler for a Firescope image. It won't be quite the same, but it will be better than nothing. Here's a link to a discussion about Firescope vs Ideal Scope:

https://www.pricescope.com/community/threads/ideal-scope-vs-firescope.3870/

 

[Stephan]

IGI excellent proportions :


crown ° : 33° to 36°


crown % : 13% to 16%


pavilion ° : 40.5° to 41.5°


pavilion % : 42% to 44%


table: 53% to 59%


girdle : thin to slightly thick


total depth : 58.5% to 62.5%




Regards,

 

[antonia]

Thanks to you both.

Stephen, do you know the Ideal cut proportions for IGI, and are they more on par with AGS excellent?

Thanks!

 

[Brian Knox]

Hi Antonia,

A couple things:

AGS has an ideal designation (zero) for cut that is rated above excellent.

You asked :

IS AGS EXCELLENT CUT EQUIVALENT TO IGI EXCELLENT CUT?

The AGS lab is much stricter than IGI, so the answer to your question is absolutely not!
Diamond professionals give much more credence to an AGS report .

Brian

 

[antonia]

Thanks.

How does IGI Ideal Cut compare agains AGS Excellent??

 

[Brian Knox]

Sorry, I don't have those parameters at my fingertips.

I just wanted to make sure that you understood that a IGI stone is not as good (almost always) as a AGS stone

Which is to say, an IGI SI-1 / E color diamond will typically be a SI-2 F color AGS diamond.

Brian

 

[antonia]

Thanks. That's ok because the stone has already been graded with GIA as E SI1, excellent symmetry and polish.... just want cut grading now so he is sending it to IGI... I doubt it will get Ideal Cut, most likely Excellent.... I wonder if that is good enough... I'll think about it.

Want to get that Idealscope image, that will surely make up my mind!