How to judge EGL cut quality

[jen2M]

My first post! I have been a lurker for while and I finally have a question! First off- I love you all for you time, help, inspiration, and letting us see all of your beautiful jewelry!

My BF and I have been together a couple years and are getting close to the point of making a purchase

Here is what we are looking for:

Round
1.7 or up
H-I
SI-1 to Si-2 (can you tell I love size)
Great cut.


I am interested in looking at EGL certs. I have free access to an independent appraiser, so I can have him take a look at any stone to make sure that the grading is close enough. My question is- how can you check the quality of an EGL cut before ordering one. From what I can see the quality cut search doesn''t include EGL and all I can find on the website listings are the depth and table.

I know this might be cutting it close but we would like to stay around 8,000

Any help you all have would be wonderful!

 

[Sparkalicious]

Hi Jen! Welcome!

My understanding is that the parameters of the "ideal" cut specs that you, for example, see on PS all the time are pretty much all standard with respect to depth, table%, crown/pavillion angles etc etc, thus, the same way that you would gauge the cut of an AGS or GIA graded stone is the same way that you would judge the EGL graded one.

When you refer to EGL, you may be referring to the "grading" process when it comes to color and clarity. Please correct me if this is not accurate. EGL Israel, for example, tends to not have the "strict" grading reputation of other labs such as AGS or GIA, thus some of their color/clarity gradings have been found to be off by up to 2 grades ... As an example, you may purchase a D, VS2 stone and pay that premium, however, when you have it appraised, it really may only be an F, Si2 stone. Just a consideration when going with an EGL graded stone.

This is just my understanding, if EGL does have "cut" standards, I am not familiar with them, however, one of the many PS experts may be and they will be happy to come along and assist you.

Good luck with finding your perfect diamond!

 

[jen2M]

Thanks for the advice. I had read on the boards that EGL-I can be very soft in their grading, so I am hoping to just have my appraser look at EGL-USA. I guess what I am wondering is how to find out all the angles and such. All I can see is the depth and table. Do I need to contact the vendor to get the other measurements? If you don''t have those to begin with- how do you even know which diamonds to ask the vendor to get more info on? Do you just base it on price, color and clarity or is there a depth and table you should stay between as well? I am sure these are really basic questions- but I am still a bit confused- what I am basically just looking for is a starting point on how to pick diamonds during the first step to examine further.

Thanks!

 

[Sparkalicious]

Date: 1/25/2008 12:34:19 AM
Author: jen2M
Thanks for the advice. I had read on the boards that EGL-I can be very soft in their grading, so I am hoping to just have my appraser look at EGL-USA. I guess what I am wondering is how to find out all the angles and such. All I can see is the depth and table. Do I need to contact the vendor to get the other measurements? If you don''t have those to begin with- how do you even know which diamonds to ask the vendor to get more info on? Do you just base it on price, color and clarity or is there a depth and table you should stay between as well? I am sure these are really basic questions- but I am still a bit confused- what I am basically just looking for is a starting point on how to pick diamonds during the first step to examine further.

Thanks!

Oh! I gotcha now, Jen!

If your EGL cert doesn''t have all the angles or percentages etc, you will likely need to ask your jeweler for a sarin report on your stone. This should give you all the measurements you need to gauge the quality of the cut. Another option, is to go to the EGL USA site an enter your certification number and see if any more info is available or you can try calling them or emailing them to see if they are able to provide it for you.

With regards to the specs for an "ideal" cut, there is a lot of info here on PS. If you are referring to a round brilliant, for example there is a certain depth & table % you should stay between if you want to ensure the best visual performance.

If you would like to do some more research go to the top of the PS page and click on the Resources tab and then on Advanced Tutorial and you should get more info than you could possibly ever need to assist you with making your decision.

Does this help to clarify?

 

[Sparkalicious]

I used the attached "ideal cut" reference as a guide when I first started looking for a diamond myself. I hope you find it helpful with regards to the %''s etc as well.

 

[jen2M]

Thanks so much for your help. There is just so much to learn!

 

[Sparkalicious]

No prob. Tell me about it!

Who knew! Have fun

 

[Lorelei]

EGL uses percents for crown and pavillion angles, which aren''t as accurate, so you could see if your vendor could run a Sarin report which gives detailed measurements of the diamond, to include angles. Also an Idealscope image would be very helpful if available.

 

[denverappraiser]

Date: 1/24/2008 11:56:44 PM
Author:jen2M

My first post! I have been a lurker for while and I finally have a question! First off- I love you all for you time, help, inspiration, and letting us see all of your beautiful jewelry!

My BF and I have been together a couple years and are getting close to the point of making a purchase

Here is what we are looking for:

Round

1.7 or up

H-I

SI-1 to Si-2 (can you tell I love size)

Great cut.




I am interested in looking at EGL certs. I have free access to an independent appraiser, so I can have him take a look at any stone to make sure that the grading is close enough. My question is- how can you check the quality of an EGL cut before ordering one. From what I can see the quality cut search doesn''t include EGL and all I can find on the website listings are the depth and table.


I know this might be cutting it close but we would like to stay around 8,000


Any help you all have would be wonderful!

A full sarin report on the stones would be very helpful. Most jewelers don’t have easy access to one but occasionally the stone supplier can get it. Failing that, have your appraiser cut grade the stones if they know how to do that. All EGL reports are not equally useful. In particular, some newer ones from EGL-USA contain quite a bit of information about the cutting.

I’m curious about your free appraiser. What do you get for your money?

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[oldminer]

"EGL uses percents for crown and pavillion angles, which aren''t as accurate, so you could see if your vendor could run a Sarin report which gives detailed measurements of the diamond, to include angles. Also an Idealscope image would be very helpful if available. "

In the world of solid geometry, or trigonometry, a solid object can be purely described with either angles or percentages. All are theoretically derived from the math and the math is 100% accurate. The problem lies in the instruments and their software programs commonly used to measure and report to gemologists. Since girdles vary in thickness, not all components of the diamonds are identical and not all components are measured. This leaves a bit of "slop" in the measures. This isn''t important to the world of diamonds, but precision people want precision data even if it has no meaning beyond numbers.

The use of percents acutually makes more sense than angles for many diamonds, but it all ends up not making a big difference. Don''t worry over it. The HCA does prefer angles, and that''s the way it was programmed, too.

 

[Lorelei]

http://www.pricescope.com/tutor/angl_vs_dpt.asp

Dave, I have always gone by what was posted in the info above regarding percentages with the HCA,would it be best to not make people aware of this in future posts? I just want to make sure I am offering the best info, regarding getting a Sarin if possible with c and p percents to get the angles, or not to worry too much.

 

[JohnQuixote]

Date: 1/24/2008 11:56:44 PM
Author:jen2M

...Here is what we are looking for:

Round
1.7 or up
H-I
SI-1 to Si-2 (can you tell I love size)
Great cut.

I am interested in looking at EGL certs. I have free access to an independent appraiser, so I can have him take a look at any stone to make sure that the grading is close enough. My question is- how can you check the quality of an EGL cut before ordering one. From what I can see the quality cut search doesn''t include EGL and all I can find on the website listings are the depth and table.

Hi Jen.

If possible I suggest you first look at GIA and AGS graded diamonds. Manufacturers choose what lab to send a diamond to on purpose, so fine-make diamonds capable of earning AGS0 or GIA EX commonly go there because reports from these labs add value. See this thread for some discussion about IGI, EGL, GIA and AGS.

I would mention, for sake of clarity, that the graphic Sparkalicious posted is a modern take on the Tolkowsky ideal (the first AGS system was based on those proportions). They are great numbers as a baseline - diamonds with proportions near Tolkowsky still tend to score at the top - and there are some other beautiful combinations that do well too.

 

[JohnQuixote]

Date: 1/25/2008 8:42:37 AM
Author: Lorelei
http://www.pricescope.com/tutor/angl_vs_dpt.asp

Dave, I have always gone by what was posted in the info above regarding percentages with the HCA,would it be best to not make people aware of this in future posts? I just want to make sure I am offering the best info, regarding getting a Sarin if possible with c and p percents to get the angles, or not to worry too much.

Hi Lady Lorelei,

Dave's right. When all data is present percentages and angles correlate. However, sometimes a diamond will have a culet present (which throws off the pavilion correlation) and since we often use integers for table% (away from Sarin, etc) crown angle can get us closer. In general I prefer angles but if all data is present, including culet, girdle range and table to XX.X% the numbers should verify each other.

You're right too, as angles are preferable for the HCA. This is because minimal data is used, but also because Garry has built in some crafty programming for sake of some logical assumptions. If you have 12 minutes these three videos might be interesting to you. Brian was trying out a new portable camera and asked Garry some FAQ that we get from consumers about HCA on his last trip 'down under.'

 

[Lorelei]

Thanks Sir John, I will have a look at those videos also!

ETA - those were really helpful videos John, thanks so much and congrats to Garry and Brian, they did a great job!

 

[jen2M]

Thanks for the advice. As for the free appraiser- he is a family member.

And I am planning on asking him for help narrowing down some options- I am just trying to get a better understanding myself.