Calling All Diamond Experts

[Leila]

I want to hear your opinions on the following 2 diamond''s idealscope--if they are comparable in appearance or if one is better than the other, or anything else you want to share. I will also post their specs. I want to know if what I am seeing can be confirmed or it''s just my imagination. Thanks.

 

[Leila]

Here''s the lightscope on the second diamond.

 

[strmrdr]

both the lightscope images look good to me.
different contrast on em.
Was the first one sent to you in email or is it off the website?
Im curius because it dont have the watermark.

 

[Leila]

Thanks for responding Strmrdr. The first lightscope is off a website. I downloaded it while back after I purchased the diamond. How are the contrasts different?

 

[strmrdr]

different color red is what I was talking about.
That explains it if the second one is newer.
He made some changes to the lightscope.
The color of the red doesnt mean anything.
its the patterns and the different colors and relationships.
Its kewl :}

They are both gog classics.

 

[Leila]

Anyone else? I will post their specs after I get some more responses. TIA.

 

[Mara]

Leila, are these the LS''s of your two stones, the 1.49 and then this 2c new one? Do you see performance differences in the new 2c stone vs the 1.49? Interested to hear what you say because the two LS''s look very nice...!!

 

[Leila]

Date: 12/17/2005 5:18:55 PM
Author: Mara
Leila, are these the LS''s of your two stones, the 1.49 and then this 2c new one? Do you see performance differences in the new 2c stone vs the 1.49? Interested to hear what you say because the two LS''s look very nice...!!

Nothing gets by you, does it Mara? Yes, these are idealscopes of my old and new diamond. I notice differences between how they look and am surprised since their idealscopes are quite similar. I don''t want to say too much yet since I want some opinions on them first. They are both beautiful though.

 

[Mara]

I thought so! I also notice differences between my old 1.29c stone and this 1.60c stone whereas to me the two idealscopes look pretty darn similar, the specs are almost spot on the same as well. The 1.60c is just a better looking stone to me. I couldn't explain how. When I was at WF I think I mentioned this and they told me that it was the lower girdle facets that made the difference. We didn't have time to explore it but I thought that was interesting.

So I wonder if maybe that has something to do with it, those nuances that maybe are not as visible in the lightscope? Possibly Jonathan can chime in since he would know the specs of both stones?

 

[Leila]

Date: 12/17/2005 5:36:46 PM
Author: Mara
I thought so! I also notice differences between my old 1.29c stone and this 1.60c stone whereas to me the two idealscopes look pretty darn similar, the specs are almost spot on the same as well. The 1.60c is just a better looking stone to me. I couldn''t explain how. When I was at WF I think I mentioned this and they told me that it was the lower girdle facets that made the difference.

Hmmm... Okay, I''m off to check if I have info on the lower girdle facets.

 

[belle]

the lgf's on those are quite similar and wouldn't contribute to any visual differences. one noteworthy difference is that the second one is cut with more contrast leakage. do you notice a difference in scintillation? another difference could be in the crown/pavilion relationship.

 

[Mr. Gemologist]

Lightscopes use polarized light to accent certain facets, hence, the "hearts and arrows" effect. In any case, if a round diamond displays the hearts and arrows, it would get no less than a Very Good on a GIA symmetry report.

 

[Rhino]

With regards to Mr. G's comments (btw, welcome to the forum Mr. G) ... what leads you to believe that our images are taken with polarized light? For clarification they aren't. Colored light is reflected into the crown as well as the shadow of the eye (or lens of a camera) as its peering through the lens. Also while it isn't common I've seen H&A stones get as low as "good" on a GIA Report.

Peace,

 

[Mr. Gemologist]

The hearts and arrows scope I use polarizes the light. Like reversing the images on a photograph. It shades the "heart" facets in the face up position, and the "arrow" facets in the pavillion up position.

I used them frequently when I worked in the lab for certain reports. As for the GIA VG to EX symmery, it is in my experience that most VG''s and all EX''s get hearts and arrows. Good syms don''t line up to get the arrow effect.

Remember, the pavillion main''s and the bezel facet points HAVE TO meet.

 

[Mara]

Possibly Leila, maybe you can ask Rhino privately what his thoughts are on the two stones and then let us know what the thoughts are? I am dying to know...!! Also want to know your thoughts on how the diamonds perform differently.

 

[JohnQuixote]

Date: 12/17/2005 7:02:10 PM
Author: Mr. Gemologist

The hearts and arrows scope I use polarizes the light. Like reversing the images on a photograph. It shades the 'heart' facets in the face up position, and the 'arrow' facets in the pavillion up position.

I used them frequently when I worked in the lab for certain reports. As for the GIA VG to EX symmery, it is in my experience that most VG's and all EX's get hearts and arrows. Good syms don't line up to get the arrow effect.

Remember, the pavillion main's and the bezel facet points HAVE TO meet.

Interesting input Mr. G.

I've seen diamonds with VG, EX and even Ideal symmetry that didn't display what I would consider enough precision in their facet relationships to call them Hearts & Arrows. Alternately, there are some diamonds cut with decent optical symmetry (enough to show a semblance of H&A) that miss EX lab-graded symmetry. Those qualities must be judged separately in my experience. More info on symmetry, here.

As for light return: We all realize, of course, that the kaleidoscopic H&A effect is an overlapping of facet reflections that is related to precision of cut - and NOT necessarily related to overall light return or performance. More info on H&A, here.

The 2 diamond images at the top of this thread are not H&A images. They were taken in a structured light environment and backlit to demonstrate their overall light return. They both display what I would consider premium light return (if they are advertised as H&A diamonds by GOG I predict they have a premium level of H&A optical symmetry as well.)

 

[Leila]

Date: 12/17/2005 7:05:18 PM
Author: Mara
Possibly Leila, maybe you can ask Rhino privately what his thoughts are on the two stones and then let us know what the thoughts are? I am dying to know...!! Also want to know your thoughts on how the diamonds perform differently.

I just sent Jonathan a PM asking him if he could share his thoughts on this. I don''t have much info on the first stone either. So hopefully he''ll chime in and then I''ll share with ya what I think.

 

[Leila]

Here are the info on diamond 1:

table 56.2
depth 60.8
crown angle 34.2-34.4
crown height 14.6-15
pavilion angle 40.7-41
pavilion depth 42.9-43.4
lower girdle facet length 78.1%

Diamond 2

table 55.6
depth 61.14
crown angle 33.9-34.2
crown height 14.9-15.2
pavilion angle 40.9-41
pavilion depth 43.2-43.4
lower halves 78% Is this the same as lower girdle facet length?

I got the lgf info from Jonathan but hopefully he will add his input soon. The difference I see is in scintillation. I wonder if the pavilion angle has to do with this. Any other thoughts?

 

[JohnQuixote]

Date: 12/20/2005 3:20:35 PM
Author: Leila

I got the lgf info from Jonathan but hopefully he will add his input soon. The difference I see is in scintillation. I wonder if the pavilion angle has to do with this. Any other thoughts?

Only that some of our local ''prosumers'' learn quickly...

Date: 12/17/2005 6:20:56 PM
Author: belle

the lgf''s on those are quite similar and wouldn''t contribute to any visual differences. one noteworthy difference is that the second one is cut with more contrast leakage. do you notice a difference in scintillation? another difference could be in the crown/pavilion relationship.

Nice job Belle and Leila.

 

[Rhino]

Hi Leila,

Really ... if you were to view both diamonds side by side in identical viewing environments, I think the only difference you would see would be in size. Larger diamonds, because of the larger facets tend to throw off slightly chunkier flashes but the 2 stones are so so similar, that were they the same size would make an awesome matching pair of studs.

Both have an excellent saturation of dark reds throughout with an awesome balance and distribution of contrast (blacks vs reds).

You would see more of a difference were you to compare those with this LS image which has a different set of proportions and minor facet cutting which represents a different flavor of H&A.

Warm regards,

 

[valeria101]

Date: 12/17/2005 7:02:10 PM
Author: Mr. Gemologist

I used them frequently when I worked in the lab for certain reports. As for the GIA VG to EX symmetry, it is in my experience that most VG''s and all EX''s get hearts and arrows. Good syms don''t line up to get the arrow effect.

The grading standard for H&A is such a slippery thing... What were you using?

I was expecting to hear this at some point, although the prevailing common knowledge on this forum (i.e. tutorial, FAQ, Glossary - reference items) emphasize that the finish grades as done in GIA terms are not identical with optical symmetry etc. Some theoretical examples and a few practical (non H&A with Vg-Vg finish - if I remember right) are listed here and there on the forum etc.

It does sound very logical that even if not all Ex-Vgs are H&A there should be allot of overlap and at least most should get close given the right proportions etc. And regardless of proportions - these should have distinct optical symmetry...

I wouldn''t insist if this wasn''t right on the fringe of the local received wisdom

Quick question:

If one would want to qualify the lowest optical symmetry for the Ex and Vg GIA finish grades... what would that look like?

 

[Leila]

Date: 12/20/2005 4:21:49 PM
Author: Rhino
I think the only difference you would see would be in size. Larger diamonds, because of the larger facets tend to throw off slightly chunkier flashes but the 2 stones are so so similar, that were they the same size would make an awesome matching pair of studs.

Jonathan, to me it seems like they have different personalities. Maybe the difference is size is throwing me off but to me, the smaller diamond had a lot of smaller flashes, whereas the llarger diamond seems to be throwing less but bigger flashes of light and seems to be more firey. Does the crown angle and pavilion angle on the larger diamond support this?

 

[Rhino]

Hi Leila,

Na. They are so close. Not enough to make any notable difference. My educated guess would be the differences in size. Here is a side by side shot of the 2 flavors of LS images posted in this thread.

 

[Rhino]

For clarification the first two LS images posted in this thread reflect the appearance of type2 in the graphic above. Type1 would be akin to the last LS image I posted. Hope this helps.

 

[Mara]

like mentioned before Leila, I agree that diff stones even with really similar specs can have different personalities, I saw it in my 1.29 and this 1.6. I can''t wait to see what kind of personality my next stone has...

 

[Leila]

And when is that gonna happen, Mara? Or has it already happened or is it happening at the moment?

Date: 12/20/2005 5:14:22 PM
Author: Rhino
Na. They are so close. Not enough to make any notable difference. My educated guess would be the differences in size.

Hmm... I''m surprise that it all comes down to size. I don''t think my new diamond is that much bigger than my last, only about 0.8 mm in size difference. Thanks for sharing your thoughts.