Diamond light performance

[Angie Nguyen]

Recently I’ve updated my wedding ring to a 1.83 ct. I thought I picked the best proportion based on the super ideal range. I sent my ring for the light performance test and I was disappointed with the result. I wonder if surface graining or faint fluorescence impacted the brilliance of the stone.
On the gemex report the brilliance and sparkle only made it to the high medium. Is this still consider a diamond with good light return?
Any feedback would be greatly appreciated.

 

[laken70]

I’m not an expert, but you diamond looks nice on paper. Have you run it through the HCA tool to see how it scores? Also, please post some pics of it. I’d love to see it!

 

[Angie Nguyen]

Here you go.

 

[laken70]

Your ring is stunning! I don’t know much about the GemEx report. I’m sure some of the experts here will be able to tell you more about that and your diamond. In addition to the HCA tool on this site, you can also plug in your diamond’s specs on diamondscreener.com and see where your diamond falls when it comes to AGS Ideal and GIA excellent.

 

[Angie Nguyen]

Thank you for the kind words. I plugged in the numbers on the HCA tool before I purchased and it came back with the score of 1.7. The one I planned to get before that has the HCA score of 1.4 but that diamond table was 60. So I went for this instead of the other one.

 

[laken70]

Anything between 1-2 is what you want. 1.4 vs 1.7, from my understanding, doesn’t mean one score is better than another. Also, I honestly think the smaller table in the diamond you chose is better, too.

I’m sure the experts here will want to see the Idealscope of your diamond to be able to better evaluate.

Honestly, I wouldn’t get too caught up in the numbers. Your diamond looks really gorgeous and just seeing the specs, I cannot see anything at all to worry about. Again, I’m not expert...just a lurker that has been learning a lot about diamonds on here!!

 

[Rhino]

Good morning.

I've used the GemEx for over a decade and have tested and studied the results of hundreds if not thousands of varying proportion sets on it. There are a few things you should bear in mind about this tech as well as why a diamond would score as it does.

1. The GemEx BrillianceScope results are based solely on direct spot lighting conditions.
2. It does show a diffuse light view for brightness but is not calculated into the results.
3. It is sensitive to leakage. If there is leakage under the table or if the upper halves are cut adversely the score will be lower.
4. Grading in mounted jewelry, while possible, is a result I would not entirely feel comfortable about. If using this exam in a buying decision it is critical the diamond be tested loose. You should have done that prior to purchase.
5. I note your report is a GIA Ex with a 34.5/41 combo with a 62% depth. While these are numbers that do in fact look good on paper it is also important to bear in mind that these are rounded numbers. Ie. Your pavilion angles may in fact be 41 degrees which if so would account for the score. As little as .1 degree on the pavilion, particularly if it's at that critical angle of 41 degrees can make or break the score.
6. On this exam, an accurately taken ASET against the flat white would further explain, confirm or deny the results on the Bscope. When I used it, I would use it in conjunction with other tech that helped one understand the results.

Hope that helps.

Rhino

 

[whitewave]

Anything between 1-2 is what you want. 1.4 vs 1.7, from my understanding, doesn’t mean one score is better than another. Also, I honestly think the smaller table in the diamond you chose is better, too.

I’m sure the experts here will want to see the Idealscope of your diamond to be able to better evaluate.

Honestly, I wouldn’t get too caught up in the numbers. Your diamond looks really gorgeous and just seeing the specs, I cannot see anything at all to worry about. Again, I’m not expert...just a lurker that has been learning a lot about diamonds on here!!

HCA is an exclusion tool, not an inclusion tool. 1-2 still needs images to evaluate performance....

 

[laken70]

HCA is an exclusion tool, not an inclusion tool. 1-2 still needs images to evaluate performance....

Yes, that’s why I said images of the diamond would help experts to better evaluate.

 

[Rhino]

just one correction to the above ...

Your pavilion angles may in fact be 41 degrees

I mean to say 41.1 at this clause.

 

[Garry H (Cut Nut)]

Further to Rhino's excellent advice from experience.

I was present when a Brilliancescope was taken apart to establish the exact lighting angles from the ring lights that create the effects. They were measured exactly and incorporated into rough diamond planning equipment that can be used by diamond cutters when fulfilling orders for retaiers selling with the Brilliancescope.

The Gemex principle can be easily cheated by diamond cutters. The red rings show the position of the lights and the flares show where light would come from and be directed straight up from the table. See the video with changing pavilion angles.

https://youtu.be/hANtfoRX2ZI

 

[Angie Nguyen]

Thank you guys for your feedback. I guess to be on the safe side I should’ve picked something between 34-40.8 since the numbers are round up. I bought this loose stone through a vendor from a local jewelry store, which I didn’t have the option to view it in person before purchasing. My local jewelry store has the strict return policy. The one thing I was able to do was select my own diamond through the online vendors and let my jeweler knows then he ordered it for me. I thought I had the right proportion so when the gemex report came back I was disappointed with the score.
Overall, would you say based on the gemex report it’s an okay light performance diamond?
I did send it in mounted in the setting, so like you said it could effect the score. Thanks.

 

[jp201845]

Thank you guys for your feedback. I guess to be on the safe side I should’ve picked something between 34-40.8 since the numbers are round up. I bought this loose stone through a vendor from a local jewelry store, which I didn’t have the option to view it in person before purchasing. My local jewelry store has the strict return policy. The one thing I was able to do was select my own diamond through the online vendors and let my jeweler knows then he ordered it for me. I thought I had the right proportion so when the gemex report came back I was disappointed with the score.
Overall, would you say based on the gemex report it’s an okay light performance diamond?
I did send it in mounted in the setting, so like you said it could effect the score. Thanks.

Safe zone for crown angle : 34 to 35
Safe zone for pavilion angle : 40.6 to 40.8

 

[Garry H (Cut Nut)]

 

[Angie Nguyen]

Wow this is good information. Thanks for sharing Gary!

 

[Diamond_Hawk]

Brilliant explanations above.

 

[Garry H (Cut Nut)]

Further to Rhino's excellent advice from experience.

I was present when a Brilliancescope was taken apart to establish the exact lighting angles from the ring lights that create the effects. They were measured exactly and incorporated into rough diamond planning equipment that can be used by diamond cutters when fulfilling orders for retaiers selling with the Brilliancescope.

The Gemex principle can be easily cheated by diamond cutters. The red rings show the position of the lights and the flares show where light would come from and be directed straight up from the table. See the video with changing pavilion angles.

https://youtu.be/hANtfoRX2ZI

Strange that the video link did not show what the video is - I thought people would find it interesting

 

[Angie Nguyen]

Do you think surface graining could effect the light return by any chance? This one has surface graining but it’s VVS2 clarity so I’m hoping it should not be too much of a concern.

 

[jp201845]

Do you think surface graining could effect the light return by any chance? This one has surface graining but it’s VVS2 clarity so I’m hoping it should not be too much of a concern.

At VVS2 clarity highly unlikely surface graining will have any impact on light performance.

 

[Garry H (Cut Nut)]

Surface graining will only ever affect reflected light.
The suface may not be super flat, which is not going to be a problem other than when you look at a reflected light with your naked eye a straight tube light may have a slight wobble.
More of a problem can be internal graining, and can be some at the surface graining intruding into the stone.
GIA often miss internal graining, even on Flawless diamonds

 

[Angie Nguyen]

I see. I learned a lot from this post. Thank you so much for your time and detail explanation. Have a good day!

 

[bright&shiny]

Strange that the video link did not show what the video is - I thought people would find it interesting

It is very interesting- the video cuts off the angle detail, but you can guess it as it repeats. I love seeing how the bands and their placement could affect the reading.

 

[Garry H (Cut Nut)]

It is very interesting- the video cuts off the angle detail, but you can guess it as it repeats. I love seeing how the bands and their placement could affect the reading.

Yes - it does. The crown is 57% and 34.5 and does not change. The pavilion angle ranges from 39.4 to 42.1 degrees. You can see how a cutter can work out the proportions of the diamonds from their regular production to send to Gemex Brillianscope retail sellers. It does not mean the stone is good or bad - just that it gets a great BS score (pun intended).

 

[Angie Nguyen]

Update: Today I received an email from Gemex telling me they’re reprocessing my diamond images since they did not use a program for diamonds in ring setting. I am much happier with the result.

 

[yssie]

This is a fascinating thread.

Thank you for posting @Angie Nguyen, and thank you @Rhino and @Garry H (Cut Nut) for such informative responses!!

I’m intrigued to see that Gemex has a different system for evaluation of set and unset stones. Makes sense. Wonder how fine-grained the settings options are - a flat-walled bezel and a three prong martini are two pretty different ecosystems for a diamond...

 

[Garry H (Cut Nut)]

This is a fascinating thread.

Thank you for posting @Angie Nguyen, and thank you @Rhino and @Garry H (Cut Nut) for such informative responses!!

I’m intrigued to see that Gemex has a different system for evaluation of set and unset stones. Makes sense. Wonder how fine-grained the settings options are - a flat-walled bezel and a three prong martini are two pretty different ecosystems for a diamond...

To the OP - what ever rocks your world
Yssie why would anyone want a system that evaluates loose diamonds?????

 

[yssie]

Yssie why would anyone want a system that evaluates loose diamonds?????