GCAL 8X Ovals?

[kb1gra]

I saw some older (well, a few months...) threads on this.

I know there was some controversy about the GCAL 8X for rounds - I see they now do ovals. I have looked at a few of them but I am wondering if there's a verdict - are these actually the best performing ovals outside of branded cuts such as the Elyque?

Full disclosure, I do NOT want an Elyque. I don't want the "most like a RB" oval, but I do want one that's not a dog. It seems there's lots of ovals out there with long pavilion mains now and the dreaded bow tie is easier to avoid. To me, the appearance of the 8x ovals I've seen is a little bit "different" so I am wondering if this is truly due to better light return or if it has to do with the cut specifications they're using?

There's a price premium for the stones graded 8X. Any opinions?

 

[Garry H (Cut Nut)]

Natural or lab grown?
If LGD tyou need to post in that forum section

 

[kb1gra]

Natural or lab grown?
If LGD tyou need to post in that forum section

The ones I was looking at were both natural and LG. I was shown both in person.

 

[autumngems]

I'd like to see one, earth mined.

 

[GCAL-Angelo]

HI Everyone - here is a Natural GCAL 8X Oval

Gem Certification & Assurance Lab

www.gcalusa.com

Unfortunately, we ran out of time during our Pricescope webinar last month (

) , but we had another half of the presentation dedicated to princess and oval that we didnt cover - we are hoping to have a chance to present that next year in a Pricescope webinar, but here are some notes and slides about 8X Fancy shapes

For the last 20 years, GCAL has been assessing the optical light performance of diamonds that pass through our lab. We’ve captured the optical symmetry, brilliance, scintillation, photomicrographs, and proportions on over a million diamonds

Here you can see just a tiny fraction of the performance images that we relied upon and data mined when establishing the 8X standards. These examples are the optical symmetry of Ovals and Princess cuts. All actual photos, no ray-traced or hypothetical images.



From all this physical and optical data that we’ve collected, we identified the highest performing diamonds. Then we isolated the proportions and angles that they shared in common.

We also correlated how variations in each cut parameter impacted aspects of light performance. From there we able to establish and set the minimum requirements for 8X

For all 8X Shapes, the first 7X's are the same (Polish, Symmetry, Proportions, Fire, Brilliance, Scintillation, Optical Symmetry). The 8th X category (for princess and oval) is called shape aesthetics.



When we considered what’s important and unique to oval brilliants for cut evaluation, the most obvious features to avoid are bowties and poor shape outlines. You’re all familiar with bow-ties –the dark area seen in the center of some ovals. The shadow caused by light blockage from the viewer.



For 8X, we are measuring this effect with machine vision to ensure all 8X Ovals have minimal bow-tie, and a nice balanced contrast.

We are also evaluating the outline shape - ovals should be a desirable ellipse shape without shoulder bulges like in this example or an uneven egg shape.



Below are the proportion ranges required for 8X Ovals. Within these ranges are where we see the highest performing ovals. For example, we limit depth percentage to 63.5% because above that depth, we almost always see a bow-tie.



But its important to understand that just because a diamond is cut with in these proportion ranges, doesn’t mean that it will qualify as an 8X. Proportions is just one of the 8 categories that must be Excellent.

Happy to answer any questions you all might have, but wanted to provide some basic information to the thread

-Angelo

 

[oldminer]

Angelo;
Is the crown angle of an oval measured at the width only, or is the range provided in the table above an average of several angles?

 

[GCAL-Angelo]

Great question @oldminer

The crown angle you see on the diagram and on the certificate is the average at the width. This is also the angle that is used in the 8X Proportion set.

The angles at the shoulders and ends are also assessed and captured - in the case of this stone, the average at the width was 34, the average at the shoulders was 33.6 and at the ends (always shallower) is 32.

The most important aspect (IMHO) about any GCAL Certificate, 8X or not, is that we are capturing actual images of the diamond in many different lighting environments, and so these nuances, that play a large role in the performance of the diamond, can't hide from the direct assessment images. They can hide from a purely proportion based system that relies on averages and limited proportion attributes, but not from direct assessment images

 

[autumngems]

HI Everyone - here is a Natural GCAL 8X Oval

Gem Certification & Assurance Lab

www.gcalusa.com

Unfortunately, we ran out of time during our Pricescope webinar last month (

) , but we had another half of the presentation dedicated to princess and oval that we didnt cover - we are hoping to have a chance to present that next year in a Pricescope webinar, but here are some notes and slides about 8X Fancy shapes

For the last 20 years, GCAL has been assessing the optical light performance of diamonds that pass through our lab. We’ve captured the optical symmetry, brilliance, scintillation, photomicrographs, and proportions on over a million diamonds

Here you can see just a tiny fraction of the performance images that we relied upon and data mined when establishing the 8X standards. These examples are the optical symmetry of Ovals and Princess cuts. All actual photos, no ray-traced or hypothetical images.



From all this physical and optical data that we’ve collected, we identified the highest performing diamonds. Then we isolated the proportions and angles that they shared in common.

We also correlated how variations in each cut parameter impacted aspects of light performance. From there we able to establish and set the minimum requirements for 8X

For all 8X Shapes, the first 7X's are the same (Polish, Symmetry, Proportions, Fire, Brilliance, Scintillation, Optical Symmetry). The 8th X category (for princess and oval) is called shape aesthetics.



When we considered what’s important and unique to oval brilliants for cut evaluation, the most obvious features to avoid are bowties and poor shape outlines. You’re all familiar with bow-ties –the dark area seen in the center of some ovals. The shadow caused by light blockage from the viewer.



For 8X, we are measuring this effect with machine vision to ensure all 8X Ovals have minimal bow-tie, and a nice balanced contrast.

We are also evaluating the outline shape - ovals should be a desirable ellipse shape without shoulder bulges like in this example or an uneven egg shape.



Below are the proportion ranges required for 8X Ovals. Within these ranges are where we see the highest performing ovals. For example, we limit depth percentage to 63.5% because above that depth, we almost always see a bow-tie.



But its important to understand that just because a diamond is cut with in these proportion ranges, doesn’t mean that it will qualify as an 8X. Proportions is just one of the 8 categories that must be Excellent.

Happy to answer any questions you all might have, but wanted to provide some basic information to the thread

-Angelo

Where can we view those earth mined that are for sale?

 

[GCAL-Angelo]

hi @autumngems - unfortunately, for almost all stones that we certify for diamond manufacturers, we don't know where they go - we have some manufacturers that literally sell to 10,000-15,000 retailers, so they could end up anywhere - i can tell you that we are working on creating this feature on our website, so that we can connect buyers to sellers for GCAL Certified diamonds, but it is not available yet

in the meantime, if you were to tell me what you are looking for, i can send a message to 8X manufacturers and see if they have anything out with a retailer that would fit close to what you are looking for

let me know

 

[Jax172]

I have been insanely curious to see one in person but they are hard to find.

 

[kb1gra]

I have been insanely curious to see one in person but they are hard to find.

I was hoping that maybe one of the vendors would have had one in that could share a video of it in real light, either on someone's hand or in tweezers - just something other than the standard videos so I can see how it translates to "on the hand."

I liked some, but not all, of the ones I saw in person, but at this point I'm second guessing myself.

 

[GCAL-Angelo]

In our experience, people have a variety of tastes in ovals, especially when it comes to L/W Ratio, which is why we allow from 1.35-1.55 in our classic 8X Oval Standard.

The L/W ratio can have a significant impact on how someone perceives an oval, but the one thing we ensure whether its 1.35 or 1.55 or anywhere in between, is that it meets all the physical specifications and light performance criteria, along with a minimal bowtie, so they should all be high performing in each iteration

@kb1gra - if you come across one that you dont like, please send me an email ([email protected]) with the cert number - all feedback is welcome

 

[Jax172]

I was hoping that maybe one of the vendors would have had one in that could share a video of it in real light, either on someone's hand or in tweezers - just something other than the standard videos so I can see how it translates to "on the hand."

I liked some, but not all, of the ones I saw in person, but at this point I'm second guessing myself.

I was interested in a lab grown one once that Frank Darling had listed. They basically refused to call it in for me to get some photos/videos of it claiming that they believed it was poorly cut. So I'm very confused.

 

[GCAL-Angelo]

@Jax172 that would be very confusing, and from all the customers i have spoken to, poorly cut has never been associated with 8X in any shape - I am not sure how i can contribute on this thread/line of comments, but what i can say...we take a lot of standardized images and videos on all the diamonds we certify, and even moreso on 8X - they are all actual - you can see the cut quality yourself

 

[RunningwithScissors]

Does GCAL (or will they in the future) have something like what you described for pear-shaped diamonds?

 

[GCAL-Angelo]

hi @RunningwithScissors - yes, the next 8X Shapes that will be released are Cushion, Radiant, Pear, and Marquise - all will be released in 2023

 

[RunningwithScissors]

hi @RunningwithScissors - yes, the next 8X Shapes that will be released are Cushion, Radiant, Pear, and Marquise - all will be released in 2023

Would love to hear you explain your grading system for the pear shape when you have it ready to present to us. I'm actively looking for a pear diamond but am finding it much more difficult than hunting for a super-ideal round. So if there will be some pears out there in the market with a perfect score from you guys in 2023, that would be incredibly helpful.

 

[GCAL-Angelo]

We definitely will - pears have similar issues (as ovals) with bowties, L/W Ratios, shoulder bulges, shape outline, etc that all dramatically impact the visual appearance of the stone. Whether its a pricescope webinar, or just a GCAL webinar, we will post it here, with a full explanation of the grading breakdown

 

[Jax172]

@Jax172 that would be very confusing, and from all the customers i have spoken to, poorly cut has never been associated with 8X in any shape - I am not sure how i can contribute on this thread/line of comments, but what i can say...we take a lot of standardized images and videos on all the diamonds we certify, and even moreso on 8X - they are all actual - you can see the cut quality yourself

Oh I have several round 8x stones that I love which is why the ovals intrigue me. I saw your images but with ovals I really wanted some real world non magnified images sparkling in different lights on a hand you know? I’m still awaiting that experience.

 

[RunningwithScissors]

We definitely will - pears have similar issues (as ovals) with bowties, L/W Ratios, shoulder bulges, shape outline, etc that all dramatically impact the visual appearance of the stone. Whether its a pricescope webinar, or just a GCAL webinar, we will post it here, with a full explanation of the grading breakdown

Awesome, thanks!

 

[GCAL-Angelo]

Oh I have several round 8x stones that I love which is why the ovals intrigue me. I saw your images but with ovals I really wanted some real world non magnified images sparkling in different lights on a hand you know? I’m still awaiting that experience.

great news on the rounds - very happy about that - let me see if we can have some videos shot of ovals or if i can get some from retail customers who have shot their own

 

[Garry H (Cut Nut)]

Congratulations Angelo. You guys are doing a great job.

 

[GCAL-Angelo]

Congratulations Angelo. You guys are doing a great job.

Thank you Garry - I greatly appreciate that, coming from you

 

[kb1gra]

great news on the rounds - very happy about that - let me see if we can have some videos shot of ovals or if i can get some from retail customers who have shot their own

thank you. This is very compelling service and would be super helpful if you end up locating some on hand video of 8X ovals. It would help us (consumers) compare with what we can see on the obviously detailed reports.

 

[kb1gra]

I was interested in a lab grown one once that Frank Darling had listed. They basically refused to call it in for me to get some photos/videos of it claiming that they believed it was poorly cut. So I'm very confused.

I should be clear that none of the ones I saw would be what I would describe as poorly cut. It was a different appearance than some of the non-8x (but still GCAL excellent) stones that I saw, but I'm trying to find the words to explain it. Almost like a white bowtie? where some of the excellent stones had more facets in that area and blended in better.

It may have to do with the ratios as Angelo says. It could also just be personal preference and the stones were objectively good.

A strange response from Frank Darling though as none of the ones I saw could remotely be described as bad.

 

[Texas Leaguer]

Congratulations Angelo. You guys are doing a great job.

@GCAL-Angelo, I second this.

I think your ability to roll out robustly researched and consistent cut grades on fancy shapes will be a huge benefit to the consumer market. Most especially to the folks in this community who are very cut quality oriented.

I look forward to you future webinars and postings on pricescope.

 

[GCAL-Angelo]

@GCAL-Angelo, I second this.

I think your ability to roll out robustly researched and consistent cut grades on fancy shapes will be a huge benefit to the consumer market. Most especially to the folks in this community who are very cut quality oriented.

I look forward to you future webinars and postings on pricescope.

thank you @Texas Leaguer - very much appreciated

wishing you all happy holidays, happy hanukkah, merry christmas, and a happy new year.

thank you all so much for your support, your kind words and yes, even your critiques!

Here's to good health and happiness in 2023 and beyond

-Angelo

 

[Jax172]

Anyone ever see a video of an 8x Oval on a hand or tweezers?