the best round diamond cut parameters: easy question, hard answers.

[Cehrabehra]

Date: 4/17/2007 6:06:02 AM
Author: Pyramid
https://www.pricescope.com/community/threads/fire-red-colors-blue.45489/


I found this old post the other day which I don''t remember seeing and in it Oldminer mentions that Tiffany actually prefer white light in their diamonds. I know these high crowns lend towards more dispersion so just thought I would link this post to show that some prefer the other edge of Storm''s limits he is looking for.

I kinda do for earrings... my earrings are always glowing white dots in pictures.... they have very shallow wide crowns and what looks (relative to the crown at least) steep deep pavillions but they don''t have a darkness in the center - they have almost no fire at all even in ideal lights and perfectly clean but they''re very bright.

 

[Cehrabehra]

Date: 4/17/2007 12:26:39 AM
Author: strmrdr

Date: 4/16/2007 9:51:03 PM
Author: Cehrabehra

Date: 4/16/2007 6:58:05 PM
Author: strmrdr
38/40.2/80/62.8

are these two both 55 table and 80 lgf? gosh, I think I like the 36 better... but I''d like this last one if the lgf were say.... 65 or so?

yep....
lgf% of 65

That''s pretty good... I''m *really* surprised they don''t offer newly cut stones along these liines at least *occasionally* as the rough provides.

 

[strmrdr]

Date: 4/17/2007 6:06:02 AM
Author: Pyramid
https://www.pricescope.com/community/threads/fire-red-colors-blue.45489/


I found this old post the other day which I don''t remember seeing and in it Oldminer mentions that Tiffany actually prefer white light in their diamonds. I know these high crowns lend towards more dispersion so just thought I would link this post to show that some prefer the other edge of Storm''s limits he is looking for.

I actualy prefere more white light return than these combos Iv posted in these threads also for use in a ring but they would be kicken in a pendant or for some one that loves fireballs.

 

[strmrdr]

Date: 4/17/2007 10:13:07 AM
Author: Cehrabehra

Date: 4/17/2007 6:06:02 AM
Author: Pyramid
https://www.pricescope.com/community/threads/fire-red-colors-blue.45489/


I found this old post the other day which I don''t remember seeing and in it Oldminer mentions that Tiffany actually prefer white light in their diamonds. I know these high crowns lend towards more dispersion so just thought I would link this post to show that some prefer the other edge of Storm''s limits he is looking for.

I kinda do for earrings... my earrings are always glowing white dots in pictures.... they have very shallow wide crowns and what looks (relative to the crown at least) steep deep pavillions but they don''t have a darkness in the center - they have almost no fire at all even in ideal lights and perfectly clean but they''re very bright.

sounds like classic 60/60s

 

[strmrdr]

Date: 4/17/2007 10:17:36 AM
Author: Cehrabehra

Date: 4/17/2007 12:26:39 AM
Author: strmrdr

Date: 4/16/2007 9:51:03 PM
Author: Cehrabehra

Date: 4/16/2007 6:58:05 PM
Author: strmrdr
38/40.2/80/62.8

are these two both 55 table and 80 lgf? gosh, I think I like the 36 better... but I''d like this last one if the lgf were say.... 65 or so?

yep....
lgf% of 65

That''s pretty good... I''m *really* surprised they don''t offer newly cut stones along these liines at least *occasionally* as the rough provides.

oec is a better option.

 

[strmrdr]

The "ideal"/best cut for a RB diamond will have great light return balanced with the right amount of contrast and cut for max scintillation.
Those are the 3 major factors in cutting for beauty.
So for the c/p angles I place the cut off where the ring of death becomes two eye visible at 10 inches on one end and the mains go dark at the other.
This will also kick out a lot of stones with too short and too long lgf% id place the cut off at 77% and 82% depending on c/p angle.
Due to its affect on scint, all painting is banned over 2 degrees and digging at .5 degrees is banned.
A diamond would have to be tighter than .3 variation pavilion and .5 crown as measured on a helium scan.
8 even hearts shall be visible in the hearts viewer.

 

[Ellen]

Oh goody, strms leaving all the fat lgf''s for us cehra.

 

[strmrdr]

Date: 4/17/2007 9:08:56 PM
Author: Ellen
Oh goody, strms leaving all the fat lgf''s for us cehra.

there can be a seperate grading system for them if ya like :}
but honestly an oec is a better bet than messing with short lgf% in my opinion.

 

[Cehrabehra]

Date: 4/17/2007 9:42:52 PM
Author: strmrdr

Date: 4/17/2007 9:08:56 PM
Author: Ellen
Oh goody, strms leaving all the fat lgf''s for us cehra.

there can be a seperate grading system for them if ya like :}
but honestly an oec is a better bet than messing with short lgf% in my opinion.

LOL! whatever makes it easier for da man

I''ll take some fat lgf''s and some skinny ones too... in fact I''ve pretty much decided that I need one of *everything* ugh... or just a job somewhere that they sell one of everything LOL!

 

[strmrdr]

Date: 4/17/2007 10:35:08 PM
Author: Cehrabehra

Date: 4/17/2007 9:42:52 PM
Author: strmrdr

Date: 4/17/2007 9:08:56 PM
Author: Ellen
Oh goody, strms leaving all the fat lgf''s for us cehra.

there can be a seperate grading system for them if ya like :}
but honestly an oec is a better bet than messing with short lgf% in my opinion.

LOL! whatever makes it easier for da man

I''ll take some fat lgf''s and some skinny ones too... in fact I''ve pretty much decided that I need one of *everything* ugh... or just a job somewhere that they sell one of everything LOL!

lol i hear ya...

This is what the labs got caught up in... some people like short lgf% so should I allow them even if they don''t fit my idea of ideal?
Now lets say the people I depend on for a living want them included...
What do I do?
Stay firm and tick people off and go broke or include them?
That is one reason the labs will not be the source of the best grading system''s.
It is too big a conflict of interest in my opinion.

 

[Cehrabehra]

Date: 4/17/2007 10:57:58 PM
Author: strmrdr
lol i hear ya...

This is what the labs got caught up in... some people like short lgf% so should I allow them even if they don''t fit my idea of ideal?
Now lets say the people I depend on for a living want them included...
What do I do?
Stay firm and tick people off and go broke or include them?
That is one reason the labs will not be the source of the best grading system''s.
It is too big a conflict of interest in my opinion.

You know, I see your point. But if grading were to continue to fall into the laps of the sellers it would be way too all over the place. I mean sure there is basic grading already but... you know what I mean, the additional light assessments etc. and I''m thinking of GIA not AGS. Anyway, I feel torn on the cushion issue because one of their charms is that none of them look alike, and rounds, gosh, the all look pretty much the same to me even though I *know* where they are different. Assuming they''re all of superb light return, I''m just talking about flavors... LGF is the single biggest flavor changer to me and with most cutters aiming for that 70-85 sort of range there''s not SO much difference than I''m left with an impression of wow, look how different that one is! They''re still beautiful, but they''re very conformed... and I''d hate that to happen to cushions. I mean, I want it to be easier for people to get the type they want, and I want them to be *well* cut rather than the crapshoot... but the individuality is one of its charms... sorry for the tangent, I know that''s not about a round LOL

 

[strmrdr]

Date: 4/17/2007 11:53:32 PM
Author: Cehrabehra

You know, I see your point. But if grading were to continue to fall into the laps of the sellers it would be way too all over the place. I mean sure there is basic grading already but... you know what I mean, the additional light assessments etc. and I''m thinking of GIA not AGS.

I think that the best grading systems will end up coming from places like MSU and individual researchers and being adopted by advanced vendors and advanced consumers.
In a lot of ways its already happening here.
Right now the best grading system in my opinion is the combo of HCA/IS/ASET/Helium/DC/hearts combined with skilled vendors and knowledgeable consumers.
It has its weaknesses over rating some shallow combos and under rating some deep ones but its better than anything else out there.

 

[Cehrabehra]

Date: 4/18/2007 12:22:26 AM
Author: strmrdr
I think that the best grading systems will end up coming from places like MSU and individual researchers and being adopted by advanced vendors and advanced consumers.
In a lot of ways its already happening here.
Right now the best grading system in my opinion is the combo of HCA/IS/ASET/Helium/DC/hearts combined with skilled vendors and knowledgeable consumers.
It has its weaknesses over rating some shallow combos and under rating some deep ones but its better than anything else out there.

I think it would be helpful if the labs told us what it was *exactly* (ie including facet plot) and then someone else took over a comprehensive light performance review. I dunno, I think as long as anyone tries to shove things into little boxes there will be flaws. We really don''t live in a digital world... it is analog after all

 

[lumpkin]

Date: 4/16/2007 8:50:22 AM
Author: Garry H (Cut Nut)

Date: 4/16/2007 8:37:38 AM
Author: oldminer
''....so American in thinking.''

Personally I take a certain degree of price in American thinking. This country is responsible for pulling the burning fat of Europe off Hitler''s griddle in WWII. We also had the task to stop Japan from conquering Asia. We ought not forget the past. Our thinking served the developed world pretty well, I believe. The ingenuity and free thinking of our educated society has also played its part in advancing technology. It wasn''t such a bad thing for many years, but there are downsides to everything, I suppose.

Point taken on the chin Dave.
Although I think if Australia was not quite so far away from Europe, and had more water, well- who knows - but we would have a Japanese Govt if the USa had not thrown a huge effort into recovering from Pearl Harbour.

On the effetiveness of your industrialization - it has worked and worked well. But there is no doubt in the minds of most not so poor people in the rest of the world - that your very high economic living standards and human education are sadly lacking in simple life style measures.

Fat may not always = happy. But lazy your nation is not. It is well led by an effective oliarchy and is blessed with plenty of lower cost labor.

But in terms of thinking outside the box - what I am prompting in my earlier post - there is a herd mentality that squashes all in its path in USA.

I''m a US customer and I picked a stone that fell outside of industry ideals, and I love my diamond. I even picked it with your help, Gary.

These are just my own preferences and I do appreciate ideal standards, I just don''t require them. Personally, Strmrdr, I don''t like natural things to be too perfect. I would have a huge range of "ideal". I don''t have to have ideal symmetry and polish, but I want it to have excellent fire, brilliance, spread and be very bright. I have had good luck with HCA and I would select using that and my eyes. This is from the perspective of a customer, not someone in the industry. I actually find the minute scrutinization of cut to be a bit tedius, as I would imagine most customers would. I take pleasure in the fact that my diamond is well cut, in that it is very brilliant and firey and I have a good spread for the weight. I don''t need to analyze it further to appreciate it.