"Disposing of a Myth - the Evolution of the Am. Rd Brilliant"

[fire&ice]

I was reading my antique rag and read a blurb about the NAJA Conference in Tucson. Our own estemed Dave Atlas is presenting "Ethics - A Responsiblity" - would love to hear a synopsis.

But, this topic caught my eye.

"Disposing of a Myth - the Evolution of the American Round Brilliant (a.k.a. American Cut and Ideal Cut, 1860-1955"

What myth is being disposed off?

 

[:)]

Very interesting - I would like to know the myth too!

 

[oldminer]

I suppose the "myth" is that ONLY a Tolkowsky parameter cut diamond is an Ideally Cut diamond. We can now show high light performance in a variety of other parameter sets. We can also create high performing non-round diamonds, such as the AGS 0 princess cut. These newer cuts might be seen as breaking the myth that only one range of parameters leads to "ideal".

Now, I didn''t suggest this topic or the name, so don''t blame me. I''m just happy to be invited to be a speaker and participant at the conference this year. I have been the Ethics Chairman of NAJA for the past 12 or 13 years. I have seen some very bad, unique and even foolish stuff in that position. It is a job fits me very well. It also encourages me to keep my own act in line.

 

[Garry H (Cut Nut)]

Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo''s of Al''s GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the ''inventor'' of the ''ideal cut'' prior to Tolkowsky''s work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

 

[JohnQuixote]

Date: 1/3/2007 3:24:13 PM
Author:fire&ice
I was reading my antique rag and read a blurb about the NAJA Conference in Tucson. Our own estemed Dave Atlas is presenting ''Ethics - A Responsiblity'' - would love to hear a synopsis.

But, this topic caught my eye.

''Disposing of a Myth - the Evolution of the American Round Brilliant (a.k.a. American Cut and Ideal Cut, 1860-1955''

What myth is being disposed off?

I asked the presenter, Al Gilbertson about it.

It''s related to material shown in his poster session at the GIA Symposium (photo below) called "The Evolution of the American Round Brilliant" and will include information from his forthcoming book which comes out later this year. Al says the NAJA presentation will be geared towards appraisers, as requested; so they can correctly recognize certain cutting styles and date them with some accuracy.

As Garry mentioned, Al is one of the pioneers of modern reflector technology.

 

[fire&ice]

Still - what''s the "myth"? I understand if he said "disposing of the mystery" - but myth?

I, in my most consumer voice, have always been told that the American Round Brilliant (thought of as a more perfect cut) was developed in America circa 1940? Again, off the cuff - I thought it had to do with the number of facets which made it "American Round Brilliant" I remember my husband''s grandmother thinking I was dissing her engagement ring b/c it was, in her words, - an older not as brilliant cut.

Of course - this is coming from a regular ethnocentric "American".

Garry - though we claim many things as our "own" - we are brilliant marketers who will put their money where their mouth is.

 

[oldminer]

Here is the "reflector" of Al himself. I''m pretty sure that his talk will be to call attention to light performance as the new Ideal Standard, versus cut to a certain parameter standard.

 

[Londonchris]

"American" anything is basically an advertisment for "Americans" to relate to.
No-one else cares too much where the brilliant cut they have is from as long as it`s good

 

[strmrdr]

Date: 1/5/2007 4:54:19 PM
Author: Londonchris
'American' anything is basically an advertisment for 'Americans' to relate to.
No-one else cares too much where the brilliant cut they have is from as long as it`s good

dems der fighting words.
Pistols at 10 yards at sunrise!
Everyone knows that adding American to the name makes it 100x better which gives France an inferiority complex.

for the humor impaired ,, laugh its funnah.

 

[pricescope]

Date: 1/5/2007 5:01:48 PM
Author: strmrdr
dems der fighting words.
Pistols at 10 yards at sunrise!
Everyone knows that adding American to the name makes it 100x better which gives France an inferiority complex.

for the humor impaired ,, laugh its funnah.

not quite, Strm. I'm sure 'fashion', 'bread', 'wine', "kiss"

, 'cuisine', 'perfume', 'cosmetics', 'impressionism', 'enlightenment', etc, sound much better with "French" in-front of them.

How about Swiss watches and Japanese or German cars? The rest is just good to go with "made in China" label

 

[diagem]

Date: 1/3/2007 5:23:46 PM
Author: Garry H (Cut Nut)
Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo''s of Al''s GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the ''inventor'' of the ''ideal cut'' prior to Tolkowsky''s work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

Garry,

Why would you say that?
Is the whole Boston Morse cutting factory a advertizing hype?

 

[Garry H (Cut Nut)]

Date: 1/5/2007 6:47:30 PM
Author: DiaGem

Date: 1/3/2007 5:23:46 PM
Author: Garry H (Cut Nut)
Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo''s of Al''s GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the ''inventor'' of the ''ideal cut'' prior to Tolkowsky''s work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

Garry,

Why would you say that?
Is the whole Boston Morse cutting factory a advertizing hype?

Morse et al recomended 40-45% tables with 35crown and 41 pavilion which do not seem to be the ideal crown and pavilion for that proportion set - AGS for 47% table for example recomend for the 41 degree pavilion angles an optimum crown angle of 33.4 to 34.2 degrees.

Some of the other historic info Al has dug up and presented at his GIA symp poster were advertising shots showing 1/3rd crown height and 2/3rds pavilion depth with tiny tables as being measures of best cut.

I think the story is a good one, but rely''s on a long bow

 

[Garry H (Cut Nut)]

I might just add to that that GIA gives a very poor grade for smaller table sizes - the smallest they go is to 47% and the 35 / 41 crown and pav data set the Good (not VG or Excellent) is right near the boundary.
http://www.diamondcut.gia.edu/charts/47_table.html
Check it out - and also do larger table sizes like http://www.diamondcut.gia.edu/charts/49_table.html and you will see the likelyhood is that the prortion sets described will get a Fair under GIA''s screwy grading system that Al helped develop!

 

[diagem]

Date: 1/5/2007 7:36:22 PM
Author: Garry H (Cut Nut)

Date: 1/5/2007 6:47:30 PM
Author: DiaGem

Date: 1/3/2007 5:23:46 PM
Author: Garry H (Cut Nut)
Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo''s of Al''s GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the ''inventor'' of the ''ideal cut'' prior to Tolkowsky''s work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

Garry,

Why would you say that?
Is the whole Boston Morse cutting factory a advertizing hype?

Morse et al recomended 40-45% tables with 35crown and 41 pavilion which do not seem to be the ideal crown and pavilion for that proportion set - AGS for 47% table for example recomend for the 41 degree pavilion angles an optimum crown angle of 33.4 to 34.2 degrees.

Some of the other historic info Al has dug up and presented at his GIA symp poster were advertising shots showing 1/3rd crown height and 2/3rds pavilion depth with tiny tables as being measures of best cut.

I think the story is a good one, but rely''s on a long bow

Fair enough, i just know that for many years round manufacturers from Belgium and Israel were cutting rounds called "American".
And these were based on the rounds that were cut in the US during the late 19th. Century.
Which were prior to "Tolkowsky 1919 Ideal".

 

[Garry H (Cut Nut)]

it is true DiaGem that the American market has a preference for smaller tables when compared to say the European and Asian markets (although not the relatively very new Japanese market).

However those markets would probably say under 60% = American and over 60% = the others. This would be a long way off 40-45% however.

 

[diagem]

Date: 1/6/2007 3:26:03 AM
Author: Garry H (Cut Nut)
it is true DiaGem that the American market has a preference for smaller tables when compared to say the European and Asian markets (although not the relatively very new Japanese market).

However those markets would probably say under 60% = American and over 60% = the others. This would be a long way off 40-45% however.

I would imagine the 40-45% would qualify for the Old-European Cuts..., than why are they not called Old-American Cut?!?!

Good question...

 

[Garry H (Cut Nut)]

That is very very funny

 

[diagem]

Date: 1/6/2007 4:35:08 AM
Author: Garry H (Cut Nut)
That is very very funny

Well at least i am happy i amused you, thats a first, no?

 

[Regular Guy]

Date: 1/5/2007 4:44:36 PM
Author: oldminer
Here is the ''reflector'' of Al himself. I''m pretty sure that his talk will be to call attention to light performance as the new Ideal Standard, versus cut to a certain parameter standard.

Late to this...but that''s a riot, Dave!

 

[JohnQuixote]

Date: 1/6/2007 2:53:08 AM
Author: DiaGem

Date: 1/5/2007 7:36:22 PM
Author: Garry H (Cut Nut)

Date: 1/5/2007 6:47:30 PM
Author: DiaGem

Date: 1/3/2007 5:23:46 PM
Author: Garry H (Cut Nut)
Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo's of Al's GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the 'inventor' of the 'ideal cut' prior to Tolkowsky's work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

Garry,

Why would you say that?
Is the whole Boston Morse cutting factory a advertizing hype?

Morse et al recomended 40-45% tables with 35crown and 41 pavilion which do not seem to be the ideal crown and pavilion for that proportion set - AGS for 47% table for example recomend for the 41 degree pavilion angles an optimum crown angle of 33.4 to 34.2 degrees.

Some of the other historic info Al has dug up and presented at his GIA symp poster were advertising shots showing 1/3rd crown height and 2/3rds pavilion depth with tiny tables as being measures of best cut.

I think the story is a good one, but rely's on a long bow

Fair enough, i just know that for many years round manufacturers from Belgium and Israel were cutting rounds called 'American'.
And these were based on the rounds that were cut in the US during the late 19th. Century.
Which were prior to 'Tolkowsky 1919 Ideal'.

Hi everyone,

This is a brief evolutionary synopsis I gathered together some time ago. Since the eyes of different continents are upon this thread, would you diamantaires be so kind as to add comments/corrections I might incorporate?

*

1650: Cardinal Mazarin designed the first cross-cut diamond, which was the beginning of the brilliant style of cutting. In the early 1700s the Portuguese diamond cutter Peruzzi refined the first 58 facet brilliant cut. This style slowly evolved throughout the 1800s, known first as the old-mine cut and later as the old-European cut. These cuts still followed the contours of the rough diamond in order to retain as much weight as possible.

1860: Henry Morse opens a diamond cutting firm in Boston. By 1880 he is recutting traditional old-European cut diamonds without regard for weight loss to produce the most beautiful round brilliant of his time.

1919: Marcel Tolkowsky’s brilliant cut emerges along with his published thesis. This work becomes the standard by which future cuts of the round brilliant, including the American Ideal Cut are fashioned.

1930: Lazare Kaplan (First cousin to M. Tolkowsky) begins cutting diamonds to Tolkowsky ideal proportions.

1931-34: Robert Shipley, the educator who popularized gemology in America, founds the GIA and the AGS.

1939: GIA launch the Gem Trade Laboratories (GTL) issuing diamond certificates for color, clarity & carat weight which are still used today.

1946: Robert Shipley makes the distinction between brilliance and scintillation in the GIA course material.

1953: Richard T. Liddicoat develops and refines a complete grading system for diamonds that include a system for evaluating cut.

1955: The AGS Diamond Standards Committee is established.

1960's: AGS develops 0-10 scale for grading diamond cut and produces the Diamond Grading Standards manual. It undergoes many revisions over the next 30 years.

1996: AGS Laboratories open and begin grading, including cut grading for the round brilliant.

2005: AGS Laboratories begins cut grading princess cuts as well as rounds and updates their system to performance-based grading.

2006: GIA laboratories updates their grading system for rounds to include cut grading.

 

[diagem]

Date: 1/6/2007 11:49:50 AM
Author: JohnQuixote

Date: 1/6/2007 2:53:08 AM
Author: DiaGem

Date: 1/5/2007 7:36:22 PM
Author: Garry H (Cut Nut)

Date: 1/5/2007 6:47:30 PM
Author: DiaGem

Date: 1/3/2007 5:23:46 PM
Author: Garry H (Cut Nut)
Someone sent me this - I think it was from an NAJA website or newsletter Dave?

I took some photo''s of Al''s GIA Symposium presentation which he asked me at the time not to publish because he will be launching a book on the topic. Looking forward to that. Remeber Al is the father of the ASET.

However i think there is a rather long bow drawn over the idea that USA was the ''inventor'' of the ''ideal cut'' prior to Tolkowsky''s work. Claims made publicly before 1918 seem to be more like advertsing hype and unpublished trade secrets are hardly evidence of anything. But history in America is, well, often American.

Garry,

Why would you say that?
Is the whole Boston Morse cutting factory a advertizing hype?

Morse et al recomended 40-45% tables with 35crown and 41 pavilion which do not seem to be the ideal crown and pavilion for that proportion set - AGS for 47% table for example recomend for the 41 degree pavilion angles an optimum crown angle of 33.4 to 34.2 degrees.

Some of the other historic info Al has dug up and presented at his GIA symp poster were advertising shots showing 1/3rd crown height and 2/3rds pavilion depth with tiny tables as being measures of best cut.

I think the story is a good one, but rely''s on a long bow

Fair enough, i just know that for many years round manufacturers from Belgium and Israel were cutting rounds called ''American''.
And these were based on the rounds that were cut in the US during the late 19th. Century.
Which were prior to ''Tolkowsky 1919 Ideal''.

Hi everyone,

This is a brief evolutionary synopsis I gathered together some time ago. Since the eyes of different continents are upon this thread, would you diamantaires be so kind as to add comments/corrections I might incorporate?

*

1650: Cardinal Mazarin designed "promoted experimental cutters'' the first ''rose-cut and double rose-cut'' cross-cut diamond, which was the beginning of the brilliant style of cutting. In the early 1700s the Portuguese diamond cutter Peruzzi refined the first 58 facet brilliant cut. This style slowly evolved throughout the 1800s, known first as the old-mine cut and later as the old-European cut. These cuts still followed the contours of the rough diamond in order to retain as much weight as possible.

1860: Henry Morse opens a diamond cutting firm in Boston. By 1880 he is recutting "Old-Mine cuts to a rounded shape" traditional old-European cut diamonds without regard for weight loss to produce the most beautiful round brilliant of his time.

1919: Marcel Tolkowsky’s brilliant cut emerges along with his published thesis. This work becomes the standard by which future cuts of the round brilliant, including the American Ideal Cut are fashioned.

1930: Lazare Kaplan (First cousin to M. Tolkowsky) begins cutting diamonds to Tolkowsky ideal proportions.

1931-34: Robert Shipley, the educator who popularized gemology in America, founds the GIA and the AGS.

1939: GIA launch the Gem Trade Laboratories (GTL) issuing diamond certificates for color, clarity & carat weight which are still used today.

1946: Robert Shipley makes the distinction between brilliance and scintillation in the GIA course material.

1953: Richard T. Liddicoat develops and refines a complete grading system for diamonds that include a system for evaluating cut.

1955: The AGS Diamond Standards Committee is established.

1960''s: AGS develops 0-10 scale for grading diamond cut and produces the Diamond Grading Standards manual. It undergoes many revisions over the next 30 years.

1996: AGS Laboratories open and begin grading, including cut grading for the round brilliant.

2005: AGS Laboratories begins cut grading princess cuts as well as rounds and updates their system to performance-based grading.

2006: GIA laboratories updates their grading system for rounds to include cut grading.

 

[JohnQuixote]

Thanks DG. I'll incorporate those.

 

[Garry H (Cut Nut)]

John that is a good summary of post Tolkowsky USA activity. Unfortunately it again perpetuautes the myth that nothing else happened anywhere outside USA.

There were several other European and even some Aussie researchers and also the first real parametric grading systems developed and implimented in Europe. Scan DN, German study teams etc. Not to mention the Japanese developing your beloved H&A''s

 

[JohnQuixote]

 

[fire&ice]

Date: 1/6/2007 7:11:25 PM
Author: JohnQuixote

Date: 1/6/2007 2:17:24 PM
Author: Garry H (Cut Nut)

John that is a good summary of post Tolkowsky USA activity. Unfortunately it again perpetuautes the myth that nothing else happened anywhere outside USA.

There were several other European and even some Aussie researchers and also the first real parametric grading systems developed and implimented in Europe. Scan DN, German study teams etc. Not to mention the Japanese developing your beloved H&A''s

Thanks Garry. Your comments & additions are welcome, so please elaborate on your second paragraph as you think appropriate. ,

Yes, if indeed one is to debunk this "myth" then site their work and related importance there of.

Again, one can play with an idea - it''s making the idea a reality/commodity, etc that sets the "ownership" apart.

 

[Garry H (Cut Nut)]

sorry F&I
I got distracted this morning.
Here is a link to an article on symmetry that gives an idea of some types of cut standards
http://www.gemology.ru/cut/english/symmetry/3.htm
There are pages either side of this one - they give some idea of the various approaches of independant European and Russian authorities.
Those with DiamCalc can check the Russian cut grades via the drop dowm in the top right.

This and the next post have pages from diamond Grading ABC Pagel-Theisen FGA 1980 edition

 

[Garry H (Cut Nut)]

These are just what is at my finger tips

 

[diagem]

Garry,

I saw a brand new finished BR 6 carats D-FL yesterday, its was GIA graded Triple EX, 32.3 degree crown, 41.8 degree pavilion.
The diamond looked real good, but do you think the 32 degree crown is a concern for re-sale purposes??

 

[strmrdr]

Date: 1/8/2007 3:54:04 AM
Author: DiaGem
Garry,

I saw a brand new finished BR 6 carats D-FL yesterday, its was GIA graded Triple EX, 32.3 degree crown, 41.8 degree pavilion.
The diamond looked real good, but do you think the 32 degree crown is a concern for re-sale purposes??

How thick was the girdle?
That shallow a pavilion angle would need a on the thick side girdle for durability reasons.
also what was the table % and lgf%?

 

[Garry H (Cut Nut)]

Date: 1/8/2007 5:18:18 AM
Author: strmrdr

Date: 1/8/2007 3:54:04 AM
Author: DiaGem
Garry,

I saw a brand new finished BR 6 carats D-FL yesterday, its was GIA graded Triple EX, 32.3 degree crown, 41.8 degree pavilion.
The diamond looked real good, but do you think the 32 degree crown is a concern for re-sale purposes??

How thick was the girdle?
That shallow a pavilion angle would need a on the thick side girdle for durability reasons.
also what was the table % and lgf%?

If the table is less than 59% and the lower girdle facets are not too long then it should be OK - some leakage, and after I have done a new version of HCA - probably not ''ideal'' or less than 2 as the pavilion is a bit deep or the crown not shallow enough. but in a bigger stone it could work fairly well.

In 5 years time the idea that certain crown angles are wrong will be ancient history.

Storn if the stone has a thin girdle as described by AGS - it would still be thick enough on a 6ct to sign your name with a fountain pen.