"American Cut - The First 100 Years," by Al Gilbertson, G.G.

Date: 10/30/2007 12:59:27 PM
Author:PS Admin

There is a new article on Pricescope journal by John Pollard.

''American Cut - The First 100 Years.'' by Al Giberston. G.G.

http://journal.pricescope.com/Articles/53/1/American-Cut---The-First-100-Years%2c-by-Al-Gilbertson%2c-GG.aspx

I want to thank him for his contribution to the Pricescope community.

Andrey
PS Admin

Great Article JohnQ..., Always good to remind ourselves and know both sides of the coin... (in this case the Atlantic)

BTW..., what was the difference between the allowed TD% between Tolkowsky and Morse?

It took me a minute to find this new forum... You're welcome of course, Andrey.

Many posters in this photo from last year's GIA Symposium are graphics in the book.  

Texas GIA alumni hosted Al last Sunday at the Royal Oaks Country Club in Dallas.  We had brunch, then his lecture and some Q&A.  Our chapter presented him with a customized glass statuette to commemorate the book's release...  Anyone who has done a project like this knows how difficult it can be.  I had a JH percussion text published, and it's labor intensive, even when you're inventing the pieces yourself.  Documenting actual history is an immense undertaking. 

Al is one of the most accessible trade leaders we have; always generous with his time and insight.  We all had a great time Sunday.

10/28/07

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Date: 10/30/2007 5:07:03 PM
Author: DiaGem

Great Article JohnQ..., Always good to remind ourselves and know both sides of the coin... (in this case the Atlantic)

BTW..., what was the difference between the allowed TD% between Tolkowsky and Morse?

Thanks DG.  Is that sea to shining sea then?...  or C to shining C?


Tolkowsky had 5 actual diamonds he spoke of in Diamond Design ranging from 55.4 - 61.4%.  His "calculated best" that we're all familiar with was 59.3% (knife-edge girdle).

I don't know that TD was something established in Morse's day.  Even the cutting angles he considered optimal are unknown.  We have to remember that these diamonds fell in a range; narrow then but wide in today's terms.  They could barely measure angles:  45/45 was the only realistic measure prior to Morse (I'll give an illustration of why).  He and Field developed an angle gauge but when you see the pictures you'll realize 'accuracy' was on a completely different planet...  He talked in broad terms about his "specimen" grade.  By the early 1900s Belgian cutters Leviticus & Polak described gauges in Europe and even these were fixed at one-degree increments (39, 40, 41 and 42 degree angles)...  That was decades after Morse.

Making a guess:  When you consider Morse's table size was 40-50%, depths around 63-65% would be logical (figuring a good sized culet).  We do have one great specimen of Morse's.  He cut the "Tiffany II" and a copper cast was made of that stone.  GIA measured it at 46T 38.8PA 36.7CA.  Depending on culet size that's in the 59-62% range.

The early way to measure angles (circa early 1800s), called the compass.  Obviously limited to 45/45.

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compass-american-cut.jpg (53.51 KiB) Viewed 237 times

Date: 10/30/2007 6:22:14 PM
Author: JohnQuixote

Date: 10/30/2007 5:07:03 PM
Author: DiaGem

Great Article JohnQ..., Always good to remind ourselves and know both sides of the coin... (in this case the Atlantic)

BTW..., what was the difference between the allowed TD% between Tolkowsky and Morse?

Thanks DG. Is that sea to shining sea then?... or C to shining C?


Tolkowsky had 5 actual diamonds he spoke of in Diamond Design ranging from 55.4 - 61.4%. His ''calculated best'' that we''re all familiar with was 59.3% (knife-edge girdle).

I don''t know that TD was something established in Morse''s day. Even the cutting angles he considered optimal are unknown. We have to remember that these diamonds fell in a range; narrow then but wide in today''s terms. They could barely measure angles: 45/45 was the only realistic measure prior to Morse (I''ll give an illustration of why). He and Field developed an angle gauge but when you see the pictures you''ll realize ''accuracy'' was on a completely different planet... He talked in broad terms about his ''specimen'' grade. By the early 1900s Belgian cutters Leviticus & Polak described gauges in Europe and even these were fixed at one-degree increments (39, 40, 41 and 42 degree angles)... That was decades after Morse.

Making a guess: When you consider Morse''s table size was 40-50%, depths around 63-65% would be logical (figuring a good sized culet). We do have one great specimen of Morse''s. He cut the ''Tiffany II'' and a copper cast was made of that stone. GIA measured it at 46T 38.8PA 36.7CA. Depending on culet size that''s in the 59-62% range.

That what I thought..., TD% was probably not established yet...
So JohnQ..., one thing does not make sense to me..., and just for the sake of discussion

From what can we understand the yields during Morse''s time were lower than during Tolkowsky"s time...

As you write "Where Morse''s diamonds had tables near 40% Wade thought Tolkowsky was right and advocated the "ideal" 53 and 54% tables he espoused."

                  "By this time the Germans were involved in cutting and, like others in Europe, they did not like the loss of weight on the crown."

Now..., my assumption would be the following based on history and knowledge...,

Morse did cut the Tiffany II..., which was a Old-Mine Cut (what we call antique cushion shape)..., which means there were ''probably'' different PA and CA on the mains and on the corners..., (not just one flat #.)  So I doubt we can use it as an example for Morse''s RB''s

Since I take the fact that Morse cut prior to Tolkowsky and prior to the rotary-saw development..., by applying a 40+/- % table to his cut would result from a combination of a steeper crown angle with a higher crown height and a knife-edge girdle which would bring a higher yield vs. Tolkowsky''s yields based on a range from 55.4 - 61.4% td.

Am I making sense???


BTW..., I still witnessed 7-8 years ago the use of the measuring tool you mention which was developed back in the early 1900s by Belgian cutters Leviticus & Polak. 

Just as I still witness a lot this present day the use of the "primitive ''Moe'' Gauge"..., I am actually amazed at the number of cutters that still use it...

Date: 10/30/2007 7:07:02 PM
Author: DiaGem

Date: 10/30/2007 6:22:14 PM
Author: JohnQuixote

Date: 10/30/2007 5:07:03 PM
Author: DiaGem

Great Article JohnQ..., Always good to remind ourselves and know both sides of the coin... (in this case the Atlantic)

BTW..., what was the difference between the allowed TD% between Tolkowsky and Morse?

Thanks DG. Is that sea to shining sea then?... or C to shining C?


Tolkowsky had 5 actual diamonds he spoke of in Diamond Design ranging from 55.4 - 61.4%. His 'calculated best' that we're all familiar with was 59.3% (knife-edge girdle).

I don't know that TD was something established in Morse's day. Even the cutting angles he considered optimal are unknown. We have to remember that these diamonds fell in a range; narrow then but wide in today's terms. They could barely measure angles: 45/45 was the only realistic measure prior to Morse (I'll give an illustration of why). He and Field developed an angle gauge but when you see the pictures you'll realize 'accuracy' was on a completely different planet... He talked in broad terms about his 'specimen' grade. By the early 1900s Belgian cutters Leviticus & Polak described gauges in Europe and even these were fixed at one-degree increments (39, 40, 41 and 42 degree angles)... That was decades after Morse.

Making a guess: When you consider Morse's table size was 40-50%, depths around 63-65% would be logical (figuring a good sized culet). We do have one great specimen of Morse's. He cut the 'Tiffany II' and a copper cast was made of that stone. GIA measured it at 46T 38.8PA 36.7CA. Depending on culet size that's in the 59-62% range.

That what I thought..., TD% was probably not established yet...
So JohnQ..., one thing does not make sense to me..., and just for the sake of discussion

From what can we understand the yields during Morse's time were lower than during Tolkowsky's time...

As you write 'Where Morse's diamonds had tables near 40% Wade thought Tolkowsky was right and advocated the 'ideal' 53 and 54% tables he espoused.'

'By this time the Germans were involved in cutting and, like others in Europe, they did not like the loss of weight on the crown.'

Now..., my assumption would be the following based on history and knowledge...,

Morse did cut the Tiffany II..., which was a Old-Mine Cut (what we call antique cushion shape)..., which means there were 'probably' different PA and CA on the mains and on the corners..., (not just one flat #.) So I doubt we can use it as an example for Morse's RB's

Since I take the fact that Morse cut prior to Tolkowsky and prior to the rotary-saw development..., by applying a 40+/- % table to his cut would result from a combination of a steeper crown angle with a higher crown height and a knife-edge girdle which would bring a higher yield vs. Tolkowsky's yields based on a range from 55.4 - 61.4% td.

Am I making sense???

You always make sense DG but I'm not sure... When you say "yield from Morse's time" are you talking about mainstream yield (in Europe) or specifically Morse's cutting works in Boston and those which followed in NY?

Good point about the T2.  Gilbertson discusses Morse's "specimen" grade for RB - his term for what evolved into Scientific Cut - but notes no 'optimal' angles.  Quote:  "pavilion angles of nearly 38 degrees could be used for shallower crowns, but we don't have a preferred pavilion angle for his 34 degree crown, nor do we know if 34 degrees is the only acceptable angle for the crown."

The imprecision of that day meant a fundamental fight was simply to put the same angle (or near-angles) all the way around on a stone.  He did a lot of recuts and one letter describing a stone to be recut into a 'specimen' noted crown angles varying from 28 to 34 degrees.

Date: 10/30/2007 7:07:02 PM
Author: DiaGem

BTW..., I still witnessed 7-8 years ago the use of the measuring tool you mention which was developed back in the early 1900s by Belgian cutters Leviticus & Polak.

Just as I still witness a lot this present day the use of the 'primitive 'Moe' Gauge'..., I am actually amazed at the number of cutters that still use it...

Yeah.  Makes me value PS.  We're in a hi-tech fishbowl here.  I know tons of pros and few can approach a deep discussion about cut like we regularly see here (though there is a Dallas recut specialist who knows his stuff).  When I opened DiamCalc during a workshop last year you would have thought I was Prometheus.

Date: 10/30/2007 8:45:23 PM
Author: JohnQuixote

there is a Dallas recut specialist who knows his stuff). When I opened DiamCalc during a workshop last year you would have thought I was Prometheus.

Sir John, tut tut
http://homepage.mac.com/cparada/GML/000Images/pim/prometheus1-3802.jpg

Does this mean that you steal fire in-order to promte brilliance?

seriously  though (Shirley) you did a great review of a seemingly immense work from al.
Well Done John

BTW as further references
http://www.folds.net/diamond/software_help.html

Jasper Paulsen occasionally posts here, and he did a great review of and made tolkowskys work accessable.

Among other things he found that:

1. Tolkowsky formulae worked for inverse table and pavilion angles. Unfortunately Mr T either missed it, or kept it as a trade secret (as many older cutters do / did).  Using some of Jaspers software you can play and get pretty similar results to mine for HCA (steeper crown and shallower pavilions work and vice a versa).

2. Jasper also proves that when a girdle is added with tolkowsky''s formula, the table size goes up. Thicker girdles need bigger tables to perform better.  Hence the 55-57% tables sizes folk around here prefer. Go play on Jaspers site.

Finally as an alien and descendant from people not so far from London, I wish to to log the claim that Morse did OK on crown and pavilion according to Al''s research.  But he kept knife edged girdles, did not mention the inverse proportion theory or practice and had commercially viable table sizes (pre saws) programmed into his methodology - even I am led to believe after saws became widely used. 
So the term "scientific cutting" could be taken with a grain of marketeering salt. 

But it is wonderful that al has dug up so much wonderful history - especially the ancient Brilliancescope that probably invalidates many current patents.

Date: 10/30/2007 8:45:23 PM
Author: JohnQuixote

You always make sense DG but I''m not sure... When you say ''yield from Morse''s time'' are you talking about mainstream yield (in Europe) or specifically Morse''s cutting works in Boston and those which followed in NY?

Good question..., I would assume i am talking about Morse''s era..., and based on the cutting techniques in the mid to end of the 19th. Century, the majority of the Diamond cutting in Europe was following the rough outline resulting in Old-Mine Cuts (or antique cushions) which came in every form or shape. So basically if Morse was the pioneer of round shaped Diamonds as the article reads:
             "...Morse''s insistence on symmetry and angles eventually resulted in the invention of the first bruting machine..."
Which that point alone means to me that the Round Brilliant was developed due to the invention of the bruting machine. And if all this happened between 1860 and 1871, it would probably prove the round brilliant was first developed and cut (on a regular basis) in America, as according to my knowledge..., round brilliants were not cut systematically in Europe at that time.

Then it would make perfect sense that: "The Europeans resisted the new style of cutting because the corners and so much of the top was lost in the process...".

But..., since the rotary-saw was developed at around 1899 (after 1860-1871)..., I still would think the Morse''s 40% tables on his pre-1899 round-brilliants would posses a deeper total depth % compared to Tolkowsky''s 53-54% tables combined with a total depth range of 55.4-61.4%..., Tolkowsky had the luxury of using "sawn" rough which Morse did not!

Good point about the T2. Gilbertson discusses Morse''s ''specimen'' grade for RB - his term for what evolved into Scientific Cut - but notes no ''optimal'' angles. Quote: ''pavilion angles of nearly 38 degrees could be used for shallower crowns, but we don''t have a preferred pavilion angle for his 34 degree crown, nor do we know if 34 degrees is the only acceptable angle for the crown.''

The imprecision of that day meant a fundamental fight was simply to put the same angle (or near-angles) all the way around on a stone. He did a lot of recuts and one letter describing a stone to be recut into a ''specimen'' noted crown angles varying from 28 to 34 degrees.

I have been cutting some cuts incorporating 28-31 degree crowns..., it works on certain types of pavilions

Date: 10/30/2007 7:07:02 PM
Author: DiaGem

BTW..., I still witnessed 7-8 years ago the use of the measuring tool you mention which was developed back in the early 1900s by Belgian cutters Leviticus & Polak.

Just as I still witness a lot this present day the use of the ''primitive ''Moe'' Gauge''..., I am actually amazed at the number of cutters that still use it...

Yeah. Makes me value PS. We''re in a hi-tech fishbowl here. I know tons of pros and few can approach a deep discussion about cut like we regularly see here (though there is a Dallas recut specialist who knows his stuff). When I opened DiamCalc during a workshop last year you would have thought I was Prometheus.

That''s a good one

i always look forward to the journal articles that our awesome experts so kindly take time to write and now we have a place where we can profess our thanks and have quality discussions about them!  what a great idea!  thanks andrey

as usual, great article john, thank you so much for sharing with us!

sounds like an awesome book for diamond geeks.
Im looking forward too reading it!

Date: 10/30/2007 5:27:53 PM
Author: JohnQuixote

Al is one of the most accessible trade leaders we have; always generous with his time and insight. We all had a great time Sunday.

John,

Congratulations on a masterfully written review of this masterful work by Al Gilbertson.

Re: "American Cut - The First 100 Years" by Al Gilbertson

Bruce and I noted the news of Al's work in the facetor's forum:

This book is finally out; I received my long-awaited copy yesterday.
Al Gilbertson, of GIA, has been working on this for years. Fascinating
photos of early diamond-cutting equipment and many references to rare
literature on diamond-cutting. Al was a hobby cutter and developed the
GilbertsonScope, used to track sources of reflected light in a gem, before he
joined GIA.
The book is available from GIA; check their website.
Bruce Harding

A few weeks ago I wrote the following to two jewelry industry
publications:

Please check out this 8min pod cast of an interview with Al
Gilbertson about the American Ideal and his book, "American Cut, the
first 100 years".

http://www.podshow.com/player/psp.php?theFeed=insidegiaedu&theEpisode=undefined <http://www.podshow.com/player/psp.php?theFeed=insidegiaedu&theEpisode=undefined>

I hope this pod cast will help you appreciate the significance of
Al's work and the importance of using the publication of his book as
an opportunity to remind the US jewelry industry, (as David Federman
did in 1985, and I did this year in the British Journal of Gemmology
and NY Diamond Magazine), that the Ideal Cut of today evolved from
uniquely American origins, namely with Henry Morse in the 1860's.
If any doubts remain in your mind about this, I would enjoy discussing it anytime.

Best/Ideal regards,

Michael Cowing

www.acagemlab.com

I sat spellbound with John at the JCK show when Mr. Gilbertson gave his presentation, and both John and I pre-ordered the book on the spot.  Little did I dream that he would get his hand delivered!  WOW!

Nice job John!

Wink

Date: 10/30/2007 6:35:58 PM
Author: JohnQuixote
The early way to measure angles (circa early 1800s), called the compass. Obviously limited to 45/45.

John,

In rereading this thread, I became curious why you said that the compass was "Obviously limited to 45/45".

I think that it was set to 45 because that was considered the best angle to fashion the evolving triple cut brilliant. If they thought 40 was the optimum, would they not have set the same compass to 40 degrees? I don't see a limitation other than the relatively crude accuracy of this early angle guage. But I believe it was purposfully set to 45 degrees, not limited to 45 degrees.

 Al sent me a copy of his book on Tuesday, but I have yet to receive it.

Just curious to know if I have missed something.

Michael

Belle, Strm and Wink - Thanks a lot.  It's a great "anytime" read - in waiting rooms, airport, etc (just don't read it in the shower Wink).

Date: 11/2/2007 10:58:39 AM
Author: michaelgem

Date: 10/30/2007 6:35:58 PM
Author: JohnQuixote
The early way to measure angles (circa early 1800s), called the compass. Obviously limited to 45/45.

John,

In rereading this thread, I became curious why you said that the compass was 'Obviously limited to 45/45'.

I think that it was set to 45 because that was considered the best angle to fashion the evolving triple cut brilliant. If they thought 40 was the optimum, would they not have set the same compass to 40 degrees? I don't see a limitation other than the relatively crude accuracy of this early angle guage. But I believe it was purposfully set to 45 degrees, not limited to 45 degrees.

Al sent me a copy of his book on Tuesday, but I have yet to receive it.

Just curious to know if I have missed something.

Michael

Michael, thanks for the kind comments.

Compass:  When you get the book, check the diagram on p. 37 (figure 2-13).

It was a simple brass plate with a hinged bar "extended at a 45 degree angle."  There was no setting the angle noted.  The book implies this was not a practice until the adjustable angle gauge developed in Morse's time.  With the compass two diamonds could be positioned as illustrated to check 45 degrees, as a function of simple geometry.  I don't know how much call there was for experimentation since most cutters just cut to whatever shape the rough diamond would yield.  Even 45/45 was in limited use and pretty sophisticated for that age.

I re-did the illustration to better reflect the tool:  The orange is the plain brass plate.  The red is the attached bar.

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JohnQ..., is the book out on the market yet?

Is it sold internationally also or in the US?

Date: 11/2/2007 10:58:39 AM
Author: michaelgem

Date: 10/30/2007 6:35:58 PM
Author: JohnQuixote
The early way to measure angles (circa early 1800s), called the compass. Obviously limited to 45/45.

John,

In rereading this thread, I became curious why you said that the compass was ''Obviously limited to 45/45''.

I think that it was set to 45 because that was considered the best angle to fashion the evolving triple cut brilliant. If they thought 40 was the optimum, would they not have set the same compass to 40 degrees? I don''t see a limitation other than the relatively crude accuracy of this early angle guage. But I believe it was purposfully set to 45 degrees, not limited to 45 degrees.

Al sent me a copy of his book on Tuesday, but I have yet to receive it.

Just curious to know if I have missed something.

Michael

Michael, thanks for the kind comments.

Compass: When you get the book, check the diagram on p. 37 (figure 2-13).

It was a simple brass plate with a hinged bar ''extended at a 45 degree angle.'' There was no setting the angle noted. The book implies this was not a practice until the adjustable angle gauge developed in Morse''s time. With the compass two diamonds could be positioned as illustrated to check 45 degrees, as a function of simple geometry. I don''t know how much call there was for experimentation since most cutters just cut to whatever shape the rough diamond would yield. Even 45/45 was in limited use and pretty sophisticated for that age.

I re-did the illustration to better reflect the tool: The orange is the plain brass plate. The red is the attached bar.

John,

Re: Congratulations on a masterfully written review of this masterful work by Al Gilbertson.

This review really showcased your educational skills.

It is so well written that GIA should consider using it in Gems and Gemology.

I don''t see how anyone could do a better job.

Michael

 

I noticed the book is now available for order on GIA''s site (unless I didn''t notice it earlier).

Here''s the exact page

DG - Swift Stebbo posted the link Al emailed me this weekend.  I'll ask Andrey to post it in the journal article as well.

Michael - wow - thanks sincerely.  I'm excited about the book and glad that comes through in my overview.  I suspect G&G would have someone with longer trade 'legs' cover such a work - but I truly appreciate the compliment.

Date: 11/5/2007 12:17:48 PM
Author: JohnQuixote

Michael - wow - thanks sincerely. I''m excited about the book and glad that comes through in my overview. I suspect G&amp;G would have someone with longer trade ''legs'' cover such a work - but I truly appreciate the compliment.

Reasonable length legs + excitement in product + excitement to write + journalistic skill = unbeatable combo.

The long-legged Sasian/Yantzer paper needed a JQ edit.

Al Gilbertson is a great artist in the diamonds and jewelry industry. The diamond cut and or American cut is never be the same without the help of the expert and continue to improved with the new equipments, accessories and materials that we used in jewelry making and diamond cut

Date: 11/9/2007 9:43:23 AM
Author: sheena
Al Gilbertson is a great artist in the diamonds and jewelry industry. The diamond cut and or American cut is never be the same without the help of the expert and continue to improved with the new equipments, accessories and materials that we used in jewelry making and diamond cut

I kind of miss old-school techniques is jewelry making...
The time and detailing used in the good old days is practically gone..., these days time is calculated and translated in to too-much value when it comes to jewelry.

Wonder if Al''s book will end up at Amazon? $36 postage (international) was a bit hard to swallow for a $29 book.

Date: 11/10/2007 1:00:17 AM
Author: stebbo

Wonder if Al''s book will end up at Amazon? $36 postage (international) was a bit hard to swallow for a $29 book.

Caramba!  I am just seeing this Stebbo - as well as your formula above - thx! :) And, frighteningly, I have considered tackling that.

If you want to contact me privately I will see what I can arrange re; getting a copy of the book to you for less in shipping.  I can''t guarantee significantly better results but our international shipping terms are good.

Date: 11/28/2007 10:29:16 AM
Author: JohnQuixote

Date: 11/10/2007 1:00:17 AM

Author: stebbo


Wonder if Al''s book will end up at Amazon? $36 postage (international) was a bit hard to swallow for a $29 book.

Caramba! I am just seeing this Stebbo - as well as your formula above - thx! :) And, frighteningly, I have considered tackling that.


If you want to contact me privately I will see what I can arrange re; getting a copy of the book to you for less in shipping. I can''t guarantee significantly better results but our international shipping terms are good.

I appreciate the offer, thanks John but only if it''s easy--I don''t want to put you out just to save a couple of bucks.