How do vendors grade cut quality of fancy shapes?

[yssie]

Karl, do you know of any (decently representative) photos/videos of those two types? I'm going through GOG's vimeos one by one searching for EC but I'm not finding much and even then I don't really know what I'm looking at..

http://vimeo.com/9964998 Type1, and it looks really lively
http://vimeo.com/34137343 ? looks like another type 1, I can't tell much about how it'll actually look in-person though
http://www.goodoldgold.com/diamond/7966 A mix - bigger table and flatter crown but with the quickly alternating bands - faster scintillation events?
http://vimeo.com/20531704

Nothing productive to add, just to say that this is a great thread and I'm following closely - thank you Lula, David, and Wink and affguy! !

Lula I can't wait to see what you wind up with And I'll be really interested to read what you think of it after owning so many Infinity RBs - I can't think of more disparate styles!


Lula, of those types which do you like best, do you think? When looking at ECs (I've only looked at a few though) I tend to favour the ones with lots of alternating bands of light and dark - more, smaller steps. I guess because that's as close to an RB as they can get in terms of both appearance and light return! I don't think I like Lula Type 3s - I get impatient waiting for those giant facet-blocks to re-orient sufficiently to *do something* - especially in larger stones...

 

[LibbyLA]

I'll try to find photos, but ebay sellers have gotten smarter about using software that prevents copying of photos off the listings. I'll have to link the listings, I guess.

Just do a screen cap of the photo and crop it if necessary. Don't know if you are Mac or PC, but there are freebies available for both, including just using PrintScreen and Paint on the PC (not what I'd recommend, but it's doable).

liz

 

[Rockdiamond]

Well cut EC's should really be divided into 2 categories both beautiful in their own way but in my experience people have a strong preference between them.

The first is what some consider to be the classic shape:
Large table and fairly low crown.
Well cut they are bright and contrasty in diffused lighting and have large fire in other lighting but very few little small flashes.
They have almost entirely large scintillation events.

Then you have the smaller tabled and high crown ones.
They are also bright but not as contrasty with more med and small virtual facets(the are still very contrasty compared to a RB)
The have a lot more flashes with more small and medium scintillation events and to many look livelier.

Well cut both should dance when tilted, this is what static images can not show and why video is nice.

Imho you can not tell an EC is the ONE until you see it in person for a couple days in your own environment but using photos and video you can separate out one that has a high potential of being the ONE.
Actually I feel the same about any diamond cut.

GREAT post Karl!!!
That is a perfectly balanced approach!
I was just looking at a flat top, overly deep emerald cut, and surprisingly, it looked pretty darn good in terms of glitter, contrast and steps.
It was a 1.00ct that looked like a .75ct- which is a cardinal sin in my eyes, but the patterning and brilliance was very nice.
In cases where a stone did not have a "bubble butt", the shallow top can look great, and also provide a large surface area.

But I also love a high crown make as well.

 

[yssie]

Too late to edit - DBL has a ton of youtubes of ECs -


Okay, this one is completely, totally *gorgeous* http://www.youtube.com/watch?v=M6_ZePTkEEk (actually kinda reminds me of Kelpie's new antique EC)

vs this one, which I personally don't like so much - I see far fewer changes as the diamond is tilted in the video plus the larger facet blocks http://www.youtube.com/watch?v=k7E6TJvGp3Y&feature=related


But then I really like this one too, w/ larger table than depth & what looks like big facet blocks http://www.youtube.com/watch?v=6IVelp6vw7A

So I'm thinking maybe I just like to see lots of stuff going on in large corners (technical commentary obviously)... and then I watch this one which I also really like, which is a complete contradiction of that http://www.youtube.com/watch?v=jZnUyuSspxk


So... I have absolutely no idea, apparently! I wish I could stare at them all for a bit in-person, I'm sure I'd have some opinions afterward

Karl, do you know of any (decently representative) photos/videos of those two types? I'm going through GOG's vimeos one by one searching for EC but I'm not finding much and even then I don't really know what I'm looking at..

http://vimeo.com/9964998 Type1, and it looks really lively
http://vimeo.com/34137343 ? looks like another type 1, I can't tell much about how it'll actually look in-person though
http://www.goodoldgold.com/diamond/7966 A mix - bigger table and flatter crown but with the quickly alternating bands - faster scintillation events?
http://vimeo.com/20531704

 

[Lula]

Thank you, yssie, Karl, Libby, and David, for your input. affguy? Are you still there? I'm hoping this is more helpful than confusing for you!

David -- I know you don't like the term "obstruction," but what I'm referring to when I use that term is the darkening of the facets of the stone. In the videos yssie linked, I heard Rhino use the term "bow tie." Whatever you term it, what I've learned in my observations is that there are some ECS where the dark area or areas are static (which is what I think Wink was referring to in his post). The stone has a distinct pattern, but the pattern doesn't move -- or "dance" -- as I think Karl put it. These stones are common and look lifeless. And I couldn't tell you right now how many of them had large tables vs small tables, shallow or deep crowns, etc. Because apparently, dull stones can occur in both "types." In a poorly cut EC, the dull, lifeless areas can take up a small part of the stone (rectangle in the center) or a large part of the stone (maltese cross or bow tie). But again, if I'm understanding this discussion correctly, the issue is not so much the pattern, but the static-ness of the pattern. Does that make sense?

Karl -- I really liked your description of the two types of ECs. Yes, that's what I see! I just haven't been able to sort out what I'm seeing into a logical framework.

yssie -- Of the two types Karl describes, I *think* I prefer the classic big tables with the fewer, larger flashes. Exactly the opposite of what I *thought* I preferred, just by the numbers. To me, it's those elegant, large flashes that differentiate an EC from all other cuts. I wouldn't kick a lively EC out of bed but, given a choice, I'll take the large, dramatic flashes of the classic type.

David, Karl, Wink, Rhino -- please post some photos/videos of the high crown/small table and lower crown/larger table types if you have them. I don't think it's an issue of which type is "better;" I think it's an issue of preference, and learning how to identify good examples of each type.

Thank you

 

[yssie]

Thank you, yssie, Karl, Libby, and David, for your input. affguy? Are you still there? I'm hoping this is more helpful than confusing for you!

David -- I know you don't like the term "obstruction," but what I'm referring to when I use that term is the darkening of the facets of the stone. In the videos yssie linked, I heard Rhino use the term "bow tie." Whatever you term it, what I've learned in my observations is that there are some ECS where the dark area or areas are static (which is what I think Wink was referring to in his post). The stone has a distinct pattern, but the pattern doesn't move -- or "dance" -- as I think Karl put it. These stones are common and look lifeless. And I couldn't tell you right now how many of them had large tables vs small tables, shallow or deep crowns, etc. Because apparently, dull stones can occur in both "types." In a poorly cut EC, the dull, lifeless areas can take up a small part of the stone (rectangle in the center) or a large part of the stone (maltese cross or bow tie). But again, if I'm understanding this discussion correctly, the issue is not so much the pattern, but the static-ness of the pattern. Does that make sense?

Karl -- I really liked your description of the two types of ECs. Yes, that's what I see! I just haven't been able to sort out what I'm seeing into a logical framework.

yssie -- Of the two types Karl describes, I *think* I prefer the classic big tables with the fewer, larger flashes. Exactly the opposite of what I *thought* I preferred, just by the numbers. To me, it's those elegant, large flashes that differentiate an EC from all other cuts. I wouldn't kick a lively EC out of bed but, given a choice, I'll take the large, dramatic flashes of the classic type.

David, Karl, Wink, Rhino -- please post some photos/videos of the high crown/small table and lower crown/larger table types if you have them. I don't think it's an issue of which type is "better;" I think it's an issue of preference, and learning how to identify good examples of each type.

Thank you

ETA: You know, I think you've nailed it. I remember seeing a 5ct+ sq emerald in Tiffany once, and the facets were huge, and largely spaced (well of course stone size was a big part of that)! Despite the fact that the patterning was much, much easier to find than in an RB I did find that it wasn't the first thing I focused on - not like with my RBs, where the overall symmetry of faceting is the first thing I focus on. But maybe I'm conditioned to note certain things in RBs whereas SCs are new to me... the fact that it was a 5ct in Tiffany lighting...

I didn't actually like it all that much. The giant rolling flashes very impressive, but the stone required far too much twisting and turning to fire them - but that's to be expected with VFs that big, I'm just more of an instant gratification kinda gal


Apparently, and apparently the same person can prefer everything just from videos!!
Check this one out - http://www.youtube.com/watch?v=M6_ZePTkEEk

 

[Lula]

Thank you, yssie, Karl, Libby, and David, for your input. affguy? Are you still there? I'm hoping this is more helpful than confusing for you!

David -- I know you don't like the term "obstruction," but what I'm referring to when I use that term is the darkening of the facets of the stone. In the videos yssie linked, I heard Rhino use the term "bow tie." Whatever you term it, what I've learned in my observations is that there are some ECS where the dark area or areas are static (which is what I think Wink was referring to in his post). The stone has a distinct pattern, but the pattern doesn't move -- or "dance" -- as I think Karl put it. These stones are common and look lifeless. And I couldn't tell you right now how many of them had large tables vs small tables, shallow or deep crowns, etc. Because apparently, dull stones can occur in both "types." In a poorly cut EC, the dull, lifeless areas can take up a small part of the stone (rectangle in the center) or a large part of the stone (maltese cross or bow tie). But again, if I'm understanding this discussion correctly, the issue is not so much the pattern, but the static-ness of the pattern. Does that make sense?

Karl -- I really liked your description of the two types of ECs. Yes, that's what I see! I just haven't been able to sort out what I'm seeing into a logical framework.

yssie -- Of the two types Karl describes, I *think* I prefer the classic big tables with the fewer, larger flashes. Exactly the opposite of what I *thought* I preferred, just by the numbers. To me, it's those elegant, large flashes that differentiate an EC from all other cuts. I wouldn't kick a lively EC out of bed but, given a choice, I'll take the large, dramatic flashes of the classic type.

David, Karl, Wink, Rhino -- please post some photos/videos of the high crown/small table and lower crown/larger table types if you have them. I don't think it's an issue of which type is "better;" I think it's an issue of preference, and learning how to identify good examples of each type.

Thank you

Apparently, and apparently the same person can prefer everything just from videos!!
Check this one out - http://www.youtube.com/watch?v=M6_ZePTkEEk

But where's the close up of the GIA report? Actually, if this one was closer to a 1:50 l/w ratio, it would be my perfect EC. What I see is a clear steps pattern, without the interference of a dark, overt, and static cross, bowtie, or rectangular pattern within the stone. I see the flashes of color and white, not the dark pattern. I'm not sure if this is an effect of the lighting in the video or due to the cutting of the stone.

 

[Karl_K]

Sorry Yssie, between the pain/pain meds for my jaw and work I don't think I will get time to look at the videos until next week.
What we should do is talk one of the vendors into doing a video of nice samples of each type.

 

[Lula]

Thank you, yssie, Karl, Libby, and David, for your input. affguy? Are you still there? I'm hoping this is more helpful than confusing for you!

David -- I know you don't like the term "obstruction," but what I'm referring to when I use that term is the darkening of the facets of the stone. In the videos yssie linked, I heard Rhino use the term "bow tie." Whatever you term it, what I've learned in my observations is that there are some ECS where the dark area or areas are static (which is what I think Wink was referring to in his post). The stone has a distinct pattern, but the pattern doesn't move -- or "dance" -- as I think Karl put it. These stones are common and look lifeless. And I couldn't tell you right now how many of them had large tables vs small tables, shallow or deep crowns, etc. Because apparently, dull stones can occur in both "types." In a poorly cut EC, the dull, lifeless areas can take up a small part of the stone (rectangle in the center) or a large part of the stone (maltese cross or bow tie). But again, if I'm understanding this discussion correctly, the issue is not so much the pattern, but the static-ness of the pattern. Does that make sense?

Karl -- I really liked your description of the two types of ECs. Yes, that's what I see! I just haven't been able to sort out what I'm seeing into a logical framework.

yssie -- Of the two types Karl describes, I *think* I prefer the classic big tables with the fewer, larger flashes. Exactly the opposite of what I *thought* I preferred, just by the numbers. To me, it's those elegant, large flashes that differentiate an EC from all other cuts. I wouldn't kick a lively EC out of bed but, given a choice, I'll take the large, dramatic flashes of the classic type.

David, Karl, Wink, Rhino -- please post some photos/videos of the high crown/small table and lower crown/larger table types if you have them. I don't think it's an issue of which type is "better;" I think it's an issue of preference, and learning how to identify good examples of each type.

Thank you

We were posting at the same time, yssie, so I missed your ETA. Yes, I had a lightbulb moment after reading Wink's "static" comment a few posts up. If that's all you see when you look at the stone, then it's a *meh* stone. The numbers don't matter. The size, color and clarity don't matter. It will just sit there like a beached (rectangular) whale. I do note in some of the videos that some ECs seem to be better at throwing off prisms of color (rather than just bright white bars of light). Again, I'm not sure if this is an artifact of lighting, or due to cutting, quality of the crystal, etc.

ETA: You know, I think you've nailed it. I remember seeing a 5ct+ sq emerald in Tiffany once, and the facets were huge, and largely spaced (well of course stone size was a big part of that)! Despite the fact that the patterning was much, much easier to find than in an RB I did find that it wasn't the first thing I focused on - not like with my RBs, where the overall symmetry of faceting is the first thing I focus on. But maybe I'm conditioned to note certain things in RBs whereas SCs are new to me... the fact that it was a 5ct in Tiffany lighting...

I didn't actually like it all that much. The giant rolling flashes very impressive, but the stone required far too much twisting and turning to fire them - but that's to be expected with VFs that big, I'm just more of an instant gratification kinda gal Heh-heh, and I prefer the stealthy flash of an EC


Apparently, and apparently the same person can prefer everything just from videos!!
Check this one out - http://www.youtube.com/watch?v=M6_ZePTkEEk

 

[Rockdiamond]

Thanks Yssie!!

Lula, just to clarify...... I don't have anything whatsoever against the term obstruction- nor the science behind it.
I guess that a large part of me has always felt over analyzation kills the joy or Art, music - or diamonds.

Lately, I've gotten more into the idea of using the analyzation ( aset for example) to develop methods to assist shoppers in comparing the type of stones I tend to love- which in many cases "break rules"- or put in a better way, call for different type of rules to be established.
The term "Crushed ice" is a perfect example.
If we're not discussing the same thing- but we're using the same name, it gets very confusing.
SO_ if we want to discuss why the stone is dark, sure, obstruction might be a great topic.
But for my daily life in picking diamonds- which can be extended to a consumer shopping for a single diamond- using visually based methods seems to work best.
Adding concepts that may very well have scientific basis seems extraneous to the way some people will shop.

If we take you as an example Lula- and you do provide an excellent example of a super educated consumer who's learned a tremendous amount here on PS..... some of the concepts when translated into your own diamond buying experience may not have been as helpful.
That is to say- if it's constantly repeated that a 14% crown height is necessary, people take their eyes off the correct ball- which is ultimately how the diamond looks to them.

ETA- Karl- consider me asked!
Lula, I'll see if I have a larger copy of the GIA report

#2 ETA- I could not find the image of the GIA report- but here's the vital stats

Emerald Cut Diamond, Loose

WEIGHT: 2.35ct
SHAPE: Emerald Cut
COLOR: E
CLARITY: VS2
MEASUREMENTS: 8.30 x 6.95 x 4.82 mm
TOTAL DEPTH: 69.4%
TABLE SIZE: 62%
POLISH: EX
SYMMETRY: VG
FLUORESCENCE: NONE
GIA REPORT #: 2115871340

Here's a shot of the stone taken in a lightbox- white background

 

[yssie]

That is an incredible stone.
Want.
Really want.

 

[Lula]

That is an incredible stone.
Want.
Really want.

I want one, too. Only mine doesn't need to be 2 carats!!

David -- So, besides the fact that it is incredibly beautiful, is this an example of a small-table, high-crown stone?

Karl -- Hope you feel better.

 

[Rockdiamond]

Suma- there is no ideal manner of photographing or taking a video.
My technique is based on the way a diamond would be assessed by a gemologist or grader
One theory might call for photographing each diamond with a consistent lens camera light etc
However what I have found is that to convey what my eyes see I need to use different methods for different stones
Personally I don't feel placing the diamond in a tray is optimal- however others find value in that type of setup.
I think this is indicative of different ways of looking at diamonds.
There is no "right" way