How significant are the star facets and lower girdles info?

[Rhino]

Now that I''ve polished my rhino''s horn.

Sir John,

I''ve just read through this thread again carefully and studied all the images you have provided.

I understand explicitly what you''re saying but I don''t think you realize exactly what we''re observing through LightScope here and *why* I am under the conviction (at this point in time) that what I am observing through the crown is the direct results of facet yaw. Everything you have written in response does not refute anything I''ve written or the results I''ve shared.

> It''s not due to out of roundness as the diamond in the example is a tightly cut stone (.04mm deviation, not enough to alter optical design to the degree that you''ve implying).
> It''s also not due to tilting. A cursory examination of the LightScope image as compared to the Gem Advisor model confirms this. The model is based on the Sarin Scan which is laid down on its table ensuring perfect leveling. If the diamond were tilted you would see the obvious difference in the patterning between the LS image and the GA model.

First let me clarify my understanding of and agreement with some of the comments you''ve made.

For clarification we are discussing the tilt of the pavilion mains NOT on the vertical or slope (north/south deviations) but on the horizontal (across the mains). The graphic below clarifies.

You had stated that facet yaw on the pavilion mains can not be observed on the pavilion mains in the face up view due to obscuration.

I would agree with this.

The twisting of the pavilion main in the horizontal direction (even in the slightest bit) can not be observed by examining the mains face up. They will appear black in reflector technology and assessing yaw on the mains in that view IS impossible. HOWEVER when you twist a pavilion main facet the direct results is what I believe I am observing in the lower girdles and in the face up position through LightScope.

I have not see anything that disproves this even in everything you have written. Next post I''ll illustrate.

 

[Rhino]

Otay Timey...

In this graphic I''ve highlighted the features I''m looking at inparticular.

As we both know ... many crown/pavilion angle combos contribute to leakage under the table (ring of death) while certain limited angles cause all the pavilion angles to function as "mirrors" (some mirrors reflecting back light vs others reflecting back obstruction).

It is my conviction that the *presence* of dark reds under the table as observed only in LightScope technology is a result of having first and foremost the proper pavilion/crown angle combos.

The length of these dark red areas (shows as dark red spikes in LS and GA pix) is dependant upon the crown/pavilion combo (slope twist relationship between crown and pavilion).

How far these dark red spikes seperate from the center of the pavilion half facets is what I believe is the result of that horizontal twist (or yaw) as the optics specifically show an east/west disorientation.

I believe Brian and I are observing the same phenomena but just through different means John.

All of the examples you''ve provided in the hearts photos are rather obvious examples of horizontal twist deviations. So in that sense ... yes ... "the hearts" become primary identifiers of this twist. I do not disagree with that. However in less obvious circumstances it is impossible to view the *face up* results of this twist unless you have a viewer that can identify the results of this h. twist in the face up view.

Since we are able to examine deviations in these reds under the table we can, at this time at least *see* numerically what deviations exist in the angles causing absence or presence of these red spikes and the length of them ... HOWEVER there are NO non-contact measuring devices that can measure the h. twist to confirm the other characteristics we are observing. We are hoping Helium will answer these questions for us and confirm numerically what we believe we''re seeing optically through LightScope.

Once Helium arrives we plan to show how those results correlate with the numerical data. If I am wrong my friend, I''m never too proud to admit it. I am always learning. Thus far I am able to observe vertical and horizontal (north/south east/west) deviations within a precision cut stone and nothing you have presented does not contradict any of my findings. Nor does Brian''s research contradict that of my own as far as I can see. As far as I can tell we are observing the same phenomena, just from differing means.

 

[JohnQuixote]

Rhino, thanks for the elaboration.

You have described precisely what I thought facet yaw was when Brian first explained it to me...Angle elevation and azimuth shift. Come on, compadre, if that's all there was to it I know you'd understand.

The dimension you didn't illustrate is a view of how diamond crystal physically reacts to the cutting wheel. It occurs when the cutter runs the facet on the wheel in a direction other than g to c (or c to g) due to graining. More material is polished away from the starting point than the end point. This unavoidably causes azimuth shift which in turn results in facet yaw. Then, polishing techniques similar to digging/painting are used to straighten the girdle and disguise what occured from the machines. They still detect the azimuth shift but not the yaw, which remains undiscovered unless seen in the pavilion view with a H&A viewer.

The three amigos who 'get it' are faceters/cutters who have laid hands on the rough and made these adjustments themselves, live.

Brian has no time to read these threads as much as he'd like, but I am going to ask him to come in and address this. His words may succeed in relaying the concept where mine have not.

 

[JohnQuixote]

Date: 8/9/2005 2:31:10 PM
Author: Rhino
Now that I''ve polished my rhino''s horn.

Don''t yaw it when you polish it!

 

[BrianTheCutter]

Greetings. It is gratifying to see public interest in the information here. Minor facets and hearts patterning have been my emphasis since the 90s. I have even been called a hearts fanatic, but millions of dollars have recently been spent for the trade to verify conclusions I have documented for years.

Rhino, there are 2 things you must understand. It is evident from what you have written thus far that you are not clear on the definition of “yaw”
In your yaw graphics all you’ve shown us is slope and azimuth shift. This is movement in the index, not facet yaw. There is still another plane to the facet. Bruce’s detailed drawing and John Q’s hearts views on page 2 show what yaw is and how to see it.
https://www.pricescope.com/community/threads/how-significant-are-the-star-facets-and-lower-girdles-info.31985/
The other is that you cannot assess yaw in the crown view, especially with a non-level stone. Your analysis is moot anyway since the hearts view you posted for your diamond doesn’t show yaw that would influence areas identified in your lightscope image. John Q tried to explain this to you.

This thread has become confused with those irrelevancies and I will try to set the record straight. Here is a process by process drawing for you and anyone who did not understand before.

Example A. The facet was run N to S. No azimuth shift.

 

[BrianTheCutter]

This is angle of the slope, what you call angle elevation.

 

[BrianTheCutter]

Example B . Due to graining and in order to allow the facet to run (which enables the diamond to be polished) he adjusted the cheater screw which resulted in the facet being taken from an E to W direction (other adjustments would be made as well, I’m not going into it). This is azimuth shift. The white line indicates the top of the girdle plane but the facet dips below it when shifted. Polishing techniques will be used to straighten the girdle in brillianteering but the fundamental damage is done.

 

[BrianTheCutter]

Example A. S to N polishing hence no azimuth shift, no yaw.

 

[BrianTheCutter]

Example A - alternate direction. N to S polishing hence no azimuth shift, no yaw.

 

[BrianTheCutter]

Example B. As the cutter polished from W to E the W side of the facet was in contact with wheel for 99% of the time and the E side for only 1% of the time so in addition to azimuth shift the resultant effect to that facet face is yaw.

 

[BrianTheCutter]

Example B - alternate example. Same thing but now from W to E. These are micron differences but it does twist the facet face (the major mirrors of light return) because you polished more diamond away from one side than the other.

 

[BrianTheCutter]

There are many tricky adjustments one makes in order to straighten up the girdle. In brillianteering the polisher camouflages the indexing issue, but the damage is done. It is undoable unless the whole bottom is repolished in the correct way. Non-contact measuring machines draw a straight line between high spots in their edge detection and do not pick up yaw. Want proof, run a stone with an indented natural on a flat facet.

Yaw is seen in a simple hearts and arrows viewer that shows its full extent. Maintaining otherwise is not productive and continuing to speculate here will only be misleading. Rhino private email John Q or me if you have more questions but I am quite certain of this.

 

[BrianTheCutter]

I assessed your light scope view but it is no good Rhino. Yaw must be seen in pavilion mains PERIOD that is fundamental to our belief in patterning. “It is all in the hearts.” If you were to sit with me and a piece of rough as it becomes a diamond I could show you the light as it were.

Another major problem is your stone is tilted so all any observation is skewed. Here is what I mean.

This is a model of a perfectly level diamond.

 

[BrianTheCutter]

Now the diamond has been tilted. Looks like azimuth shift but it is not azimuth shift. This is a perfect computer model but tilted. This is our biggest problem with any crown evaluation and why ASET has a table based platform (smart move by AGS!). They realized it from day 1.

 

[BrianTheCutter]

Your diamond was tilted all along so your evaluation is invalid Rhino. Your enthusiasm is appreciated but the incorrect interpretations mislead your followers. Meanwhile John Q has tried to help you away from this path.

I will compliment you on this. If your diamond was level it might be possible to see (some) ancillary yaw or effect in lower halves. In actual fact it may be interesting to have some yaw in upper & lower halves as it may enhance scintillation. This needs to be considered. I am not saying good or bad but it is a point worth study.

 

[BrianTheCutter]

My friend, I am grateful that communication is taking place but some tediousness would have been prevented if you had asked questions rather than representing things as facts. This is not your area of proficiency. Unless you have sat at a wheel you will not understand diamond graining and the way it reacts under your hands. This is why you have not understood yaw. My studies date back to the 90s. I was evaluating diamonds for cut back then with reflectors and backlighting. I have worked to find ways to reduce yaw for over a decade and have been successful in my spheres of influence.

Rhino you’re very enthusiastic in the work you do but be careful not to let your enthusiasm masquerade as expertise. Remember that your consumer congregation believes all you say. They trust you and get angry when someone else corrects you. We tried for 3 pages here. Whiteflash may yet draw fire from your congregation for my setting the record straight here.

I am working to improve cut quality everywhere along with my peers, so it is important that information on this phenomenon be spread accurately. That is the reason for our urgency.

My hand is always extended. If you wish to consult with me in my area of expertise we can seek mutual time for discussion (which may be harder than understanding yaw).

 

[BrianTheCutter]

Strmrdr, hello. It is good to see you still around as ever.

John Q stated our research on minor proportions above. As a leader in the field of cut we have a responsibility not only to ourselves, but to all consumers -not just those who shop with us- to deliver complete information on our assessments. ACA can be cut to any proportions I choose. I could emulate any diamond design in the world or go completely proprietary and make little poodles or something. We have great expertise and this is dedicated professional research that should be shared with the community, outlined for what it is: A prescription for best visual balance from one recognized authority in the field of cut. If we had not proved this for ourselves we would simply cut our diamonds differently. Some people want to know why we do what we do and here is the information, thank you kindly.

That is not to say we know it all. We don’t. We are an authority but we are not arrogant. I learn from others and others learn from me. We never said we cut the world’s most perfect diamond but we do claim a most visually balanced diamond. This is after intense research spanning decades and cutting countless diamonds, corroborated with massive feedback. It is not a claim we make lightly.

There are no magic chicken eggs, Strm, just decades of planning and cutting and analysis. By the way Strm, since you insist on such great patterning in asschers maybe you should emphasize the same in rounds as we suggest… Speaking of which, when are you going to get on the stick and learn to polish rough so you can head up my square emerald cut production there, mister Strm?

 

[strmrdr]

Brian,
First thank you for the awesome presentation on yaw.
Since you decided to address some issues in public im going to also.
If that is how this was handled in the first place it
would have resulted in a lot less problems.
The problem was not the disagreement but in how it was handled.
If anyone had treated John or you that way my responce would have
been the same as would all of the others.

Thats all im going to say in public about it im available by PM, Email or yahoo chat, John knows how to find me.

As for your post addressed specificaly to me Ill address it later right now my Pepsi glass is empty and thats not good :}

 

[Rhino]

Hi Brian!

Good to cya around mate. Thank you for sharing. I would like to continue to ask further questions. If you like I can do this via pm or email however if we tackle it here on the forum perhaps everyone including myself will benefit from the conversation. After all I don't claim to know it all and I have not spent one second at a cutters wheel to know the feel of graining on the hand etc. At the same time however I have probably spent more time analyzing and photographing diamonds under what is perhaps the broadest array of optical measuring devices that can be had on this planet along with the best available measuring devices for doing such. Since you have resurfaced this thread there are some issues and questions and points I'd like to put forward to you friend.

1. I have read your posts and studied your images Brian. I do not doubt one iota what your saying regarding your observance of this phenomena in the H&A viewer. I FULLY AGREE. The one question however that remains unanswered (which I believe I have) is "How does this phenomena affect the face up appearance of a diamond?" How does it show this optically and in the positoin that concerns the consumer most? The face up position? We can analyze the affects of the deviation of azimuth shift which as you point out results in yaw, but if we can not demonstrate to a client how this impacts the face up appearance, IMO the conversation is moot or unimportant. When we put ourselves into the shoes of John Q. Public and start speaking about these things, if the results of this is something that can only be observed upside down in a Hearts & Arrows viewer ... what's the point? My conviction thus far from what I am gathering from all the information shared in this thread is that we are both observing the results of the same phenomena but through different means Brian. You are pointing out these east/west deviations through the pavilion in an H&A viewer. I am observing the these east/west deviations through the crown in LightScope. Why is this so hard to grasp? Why can I not be observing this phenomena? You do believe it has an impact on face up appearance no? Don't you believe this can be seen optically through images in DiamCalc? IF not DC then what? I don't doubt or question your expertise for one moment Brian but at the same time, while we both work with and photograph through reflector technology are you open to the fact that the scope we have produced may show more detail? Including the face up results of azimuth shift resulting in facet yaw? Earlier in this thread I said something to the effect "If the alignment of the facets show no yaw you will get perfect optical alignment of the reds which can be primarily seen under the table. The more the facets are tilted in the east/west orientation the more you will see deviation and seperation in the reds in LightScope." I didn't word it exactly like that but the gist was there.


2. Brian, I know for a fact that my stone in the photograph is not tilted. How do I know this? Very simple. The Sarin scan is done table down and is perfectly flat. The image generated by DiamCalc of that model is that of a perfectly centered stone with no tilt. My photograph (the one I had posted before the one above showing the DC image next to my photograph) shows the east-west shift in the reds as observed identically in my photograph. Since both the DC image and my photograph are perfectly centered, the east/west shifts we are observing in the reds are what we believe is exactly what you are talking about. Since there is not a device available that can measure this numerically at this moment YES ... I can't demonstrate by the numbers what these east/west shifts in the reds are which is why you do not see a tutorial from us on this subject. When we get Helium we hope to complete our own personal research on the subject, demonstating how this phenomena impacts face up appearance which can be illustrated both with LightScope technology and also by the numbers as well. If the numbers do not confirm what we are observing then it'll be back to square one. The topic of my current research is exactly this Brian however I've come to a stand still until I can get hard data that confirms what we are observing. We need a device that shows azimuth shift resulting in facet yaw so it can be demonstrated why this is important to John Q. Public in patterned diamonds.

Those east/west left/right shifts (which I tried to demonstrate in the black/white graphic I had posted) in the red patterns we observe in LightScope are still ... to my conviction identical to what you're describing in your graphics. There is no contradiction in what we're talking about that I see. If so, please point it out to me. I tried (perhaps not accurately enough) to demonstrate what you have in your graphics just posted. THIS IS THE EXACT DISORIENTATION I am talking about in this thread. You see ... there is nothing you or John have written with which I do not agree with here. We are all on the same page as far as i can see. What I am referring to (rather crudely) as the "horizontal" shift in facet alignment is exactly what your graphics are demonstrating.

I would maintain that when there is no tilt in the east/west orientation you will have no yaw or no azimuth shift.

I'm sorry if I wasn't using the correct terminology. Perhaps if I had said it using shift in azimuth instead of horizontal orientation I would have been clearer. I apologize for that.

When John stated earlier (quoting you I would assume) "Yaw influences angular path." and "Yaw alters visual balance" I believe I am observing this in our technology and I have not read anything that leads me to believe otherwise.

So Brian ... if my stone is indeed perfectly centered in the photograph what would you say is this disorientation we see in the reds when they are not perfectly aligned?

I look forward to further correspondence with you on this subject.

If you agree, and it appears we are indeed on the same page, perhaps we can co-author an article on the subject and combine our energies to educate the public about this phenomena? I already have something in the works but have put off completing it until Helium arrives. Once I am completed perhaps we can get our heads together on this more eh?

 

[Garry H (Cut Nut)]

Rhino here is an exercise:

1. Model a diamcalc stone with the average angles of your stone above.
2. Save it as a DXF file under Cut > Export >AutoDesk DXF (see this thread post 22 for help https://www.pricescope.com/community/threads/user-tips-for-diamcalc.32366/ )
3. Open the stone model you saved in the same way Cut> Import> AutoDesk DXF
4. now open the advanced tab on the lower right
5. open a new DiamCalc and open the stone above
6. open its advanced tab on the lower right also
7. Then compare the deviations in each facet for azimuth and slope (facet angle)

Brian, as we discussed this in Vegas, any flat facet can be described as a plane in a virual space by two (only two) angles. Azimuth and slope are enough. What you are describing is a bit of azimuth and a bit of slope change.

Rhino, if you do as I say you will find the offending facets. you will even be able to correct them using the tools in advanced - effectively recutting, the stone with aximuth and slope - you can even 'unpolish' the facets.

 

[strmrdr]

Date: 8/15/2005 12:35:04 AM
Author: BrianTheCutter
Strmrdr, hello. It is good to see you still around as ever.

likewise nice to see you post here



John Q stated our research on minor proportions above. As a leader in the field of cut we have a responsibility not only to ourselves, but to all consumers -not just those who shop with us- to deliver complete information on our assessments. ACA can be cut to any proportions I choose. I could emulate any diamond design in the world or go completely proprietary and make little poodles or something. We have great expertise and this is dedicated professional research that should be shared with the community, outlined for what it is: A prescription for best visual balance from one recognized authority in the field of cut. If we had not proved this for ourselves we would simply cut our diamonds differently. Some people want to know why we do what we do and here is the information, thank you kindly.

Im not going to re-open that can of worms. Edits have been made and apologies issued and its settled.



That is not to say we know it all. We don’t. We are an authority but we are not arrogant. I learn from others and others learn from me. We never said we cut the world’s most perfect diamond but we do claim a most visually balanced diamond. This is after intense research spanning decades and cutting countless diamonds, corroborated with massive feedback. It is not a claim we make lightly.

Im going to take this opertunity to bug you about providing heart images on the website. I just cant pass it up :} I do see it as arrogant to want the title of the formost athority on true h&a and not put the images up where others do so. I wont have a double standard, either I want to see them up front from everyone who I recomend or Im fine with everyone not showing them I cant have it both ways. I think we all know where I stand on the issue. Iv heard about the guarentee a million times and if it serves the majority of your market then so be it. That doesnt change my opinion.

There are no magic chicken eggs, Strm, just decades of planning and cutting and analysis.

I respect and admire that and it combined with the quality of your diamonds and WF service go a long way for making up for any shortfalls which is why WF is on my shortlist of highly rated internet diamond dealers.
No company and no person is perfect Im about as far from perfect as one can get.


By the way Strm, since you insist on such great patterning in asschers maybe you should emphasize the same in rounds as we suggest…

I tried that and got creamed for having a "strmrdr standard" for true h&a and not following your standard which is impossible because there arent enough examples around. The only major area we disagree on is clefts in the hearts. Iv spent hours with Jon and John talking lgf% and have within my limited means looked at diamonds cut both ways and have to come to the conclusion that both are valid ways to cut a diamond with some advantages going both ways and its a personality issue not a quality issue as long as they arent too long or short.


Speaking of which, when are you going to get on the stick and learn to polish rough so you can head up my square emerald cut production there, mister Strm?

Iv been eyeing a faceting machine but for now I have far more pressing matters to deal with.

Nice talking to you Brian some of this is much better discussed in private and most of it has been hashed out with John allready but you know how to contact me.

 

[Rhino]

Date: 8/15/2005 4:19:37 AM
Author: Garry H (Cut Nut)
Rhino here is an exercise:

1. Model a diamcalc stone with the average angles of your stone above.
2. Save it as a DXF file under Cut > Export >AutoDesk DXF (see this thread post 22 for help https://www.pricescope.com/community/threads/user-tips-for-diamcalc.32366/ )
3. Open the stone model you saved in the same way Cut> Import> AutoDesk DXF
4. now open the advanced tab on the lower right
5. open a new DiamCalc and open the stone above
6. open its advanced tab on the lower right also
7. Then compare the deviations in each facet for azimuth and slope (facet angle)

Brian, as we discussed this in Vegas, any flat facet can be described as a plane in a virual space by two (only two) angles. Azimuth and slope are enough. What you are describing is a bit of azimuth and a bit of slope change.

Rhino, if you do as I say you will find the offending facets. you will even be able to correct them using the tools in advanced - effectively recutting, the stone with aximuth and slope - you can even ''unpolish'' the facets.

Thanks Garry. Once I get back on my laptop I''ll do this.

I understand what you''re saying regarding azimuth and slope are enough. Perhaps we should digress to simpler language which may be better understood where yaw is used in a different but similar context.

Like that in which it is used in flight. When flying an aircraft you have the characteristics of flight which are pitch, roll and yaw.

Pitch = slope (actual pavilon angle)
Roll = change in azimuth or altering the horizontal angle of the pavilion facet
Yaw = the left/right east/west shift that results

Pitch/slope: In an airplane when you pull back on the stick or push forward you are altering pitch resulting in either moving at an upwards or downwards angle.
In a diamond altering the pitch or slope would either increase or decrease the pavilion angle.

Roll/azimuth: When flying an airplane when you pull the stick to the left or right you roll the plane.
In a diamond this isn''t easily observable but there is an altering of the pavilion angle on the horizontal plane. ie. twisting it. (btw ... if I am wrong in my understanding of *any* of this guys, please feel free to correct me).

Yaw: In an airplane controlled by the rudders resulting in an east/west left/right shift in flight.
In a diamond from what I am gathering here Brian you are saying that this left/right shift is the result of roll/azimuth change in the pavilion main.

You are saying that in diamonds azimuth is directly related to yaw. Or in other words yaw is the direct result of azimuth shift. No shift in azimuth would result in no yaw.

Am I understanding you correctly?

 

[sjr]

Just wanted to thank you guys as a consumer from keeping this in PM (well as far as I can tell). This is probably my most favorite informative thread in my limited obsession of this site- from all perspectives!

 

[WinkHPD]

Brian,

Thank you for explaining Yaw in a fashion that even the mathmatically challenged Wink can understand. I am in awe of the work that some of you do and greatful that it is being done.

Next year I will coordinate with Sr. Quixote to make sure that our time in Vegas overlaps. I would like to meet you face to face someday.

Wink

 

[strmrdr]

Date: 8/15/2005 4:42:20 PM
Author: sjr
Just wanted to thank you guys as a consumer from keeping this in PM (well as far as I can tell). This is probably my most favorite informative thread in my limited obsession of this site- from all perspectives!

As time goes on here you will find that some of the most informative and interesting threads here are when Jon and Brian disagree on something.
Brian is a master diamond cutter and Jon is a master diamond observer/cut grader.
They are both very good at explaining and stating their case in an understandable manner.
When they are both at the top of their game its awesome and we learn a lot from it.
This thread for a little bit went out of bounds but it speaks to the quality of the people involved that apologies were made and edits made and things went back to a reasonable discussion.
When people are very passionate about what they do its normal for things to get a little hot at times.

Im looking forward to learning more in this thread and others as the concept of yaw is more fully explored.

 

[belle]

Date: 8/15/2005 9:18:11 AM
Author: strmrdr

Im going to take this opertunity to bug you about providing heart images on the website. I just cant pass it up :} I do see it as arrogant to want the title of the formost athority on true h&a and not put the images up where others do so. I wont have a double standard, either I want to see them up front from everyone who I recomend or Im fine with everyone not showing them I cant have it both ways. I think we all know where I stand on the issue. Iv heard about the guarentee a million times and if it serves the majority of your market then so be it. That doesnt change my opinion.

i totally agree with strm here. brian is the authority on hearts and arrows, so it would be good if we could see some examples of his work.

after doing much searching of the wf site and knowing what i do about their volume now, i can see their side of this issue too. they have near a thousand diamonds in stock. no other vendor who gives as much info even comes close. not even by half. it’s pretty amazing that they even have ideal scopes, sarins and certs online for all those. for some stones that i have looked at, it seems they are gone just after the images go up, so i could see how keeping up with images would prove difficult.

maybe a compromise....(?) you could start with displaying a page of some of the h&a requests made be individuals if you have them available.... just let us see some hearts!

 

[JohnQuixote]

Jon, Garry, Strm, Belle... Will reply if time allows a bit later. Been swamped for the last few days.

 

[Rhino]

Thinking about this discussion I could *easily* see how one could confuse the difference between azimuth deviation and yaw. They almost appear to be one and the same thing and even in some of the things I have written in this thread I could see how it could be construed as one and the same. Hence I do understand John''s (and perhaps Brians) frustration with the thread.

I hope the explanation of pitch, roll and yaw helped make it more clear on my understanding of the subject but Brian''s graphics (particularly the one done by Bruce Harding on the 1st or 2nd page) demonstrates it perfectly.

On another note I have been carefully examinging the reports produced by Helium and dayum!... we''ll be able to measure azimuth deviation not just on pavilion mains but every single facet on the diamond in question.

While Brian has mastered the analysis of this phenomena on the pavilion through an H&A viewer the focus of my personal study has been on the impact of this in the face up appearance and is what we will be publishing in an upcoming article.

For clarification and to Brian''s credit let me make something clear. Brian is the first one to identify and describe this phenomena of *yaw* and to my knowledge the first person to be able to identify it on the pavilion in an H&A viewer. I seriously doubt ANY other cutter can do this. I was aware and familiar with slope and azimuth but when John mentioned yaw to me at the JCK show I knew he was speaking of something that directly correllated with these elements and from the simulated flight training I''ve done (on my computer) knew it wasn''t exactly the same as azimuth although it is directly tied into azimuth.

The focus of my studies since we have develped LightScope technology have been what instances produced the richest and darkest reds observed under it in the face up view (particularly under the table), which is primarily affected by the slope (pavilion angles) but secondly by this combination of azimuth deviation and yaw. Had John not mentoined yaw at the JCK show I''d probably only be observing effects of azimuth under LightScope and noting other differences if azimuth between 2 stones were the same but produced different optical results. As I mentioned earlier I do not want to publish *anything* concrete on this until I have the means to measure it physically.

Honestly ... this is all very exciting as we are making discoveries not yet made in the world of diamonds and it is very exciting to be a part of it all. I am sure Brian is equally as excited if not moreso. Making discoveries and exploring unchartered territories keep this adventurous and FUN!

As a Gman my personal endeavors revolve around the study of the optical signature of diamonds and being able to identify what signatures produce the desired results that the end client desires most in their stone.

Peace out,

 

[Dancing Fire]

Date: 8/17/2005 2:53:43 PM
Author: belle

Date: 8/15/2005 9:18:11 AM
Author: strmrdr

Im going to take this opertunity to bug you about providing heart images on the website. I just cant pass it up :} I do see it as arrogant to want the title of the formost athority on true h&a and not put the images up where others do so. I wont have a double standard, either I want to see them up front from everyone who I recomend or Im fine with everyone not showing them I cant have it both ways. I think we all know where I stand on the issue. Iv heard about the guarentee a million times and if it serves the majority of your market then so be it. That doesnt change my opinion.

i totally agree with strm here. brian is the authority on hearts and arrows, so it would be good if we could see some examples of his work.

after doing much searching of the wf site and knowing what i do about their volume now, i can see their side of this issue too. they have near a thousand diamonds in stock. no other vendor who gives as much info even comes close. not even by half. it’s pretty amazing that they even have ideal scopes, sarins and certs online for all those. for some stones that i have looked at, it seems they are gone just after the images go up, so i could see how keeping up with images would prove difficult.

maybe a compromise....(?) you could start with displaying a page of some of the h&a requests made be individuals if you have them available.... just let us see some hearts!

yes...would love to see some ACA hearts.

 

[Paul-Antwerp]

Yawn,

I think that I deserve a medal for reading through all this, and remaining attentive. It probably is because I still understand what each person is saying, and the fact that I just returned from a true holiday is also helpful.

Anyway, what I see here is a classical example of people defending their opinion, without really understanding what the other person is defending.

In this, being a cutter and knowing what happens at the wheel, I fully understand what Brian and John are trying to explain. When we last met in Vegas, we agreed that we do not know yet to which extent the presence of facet yaw is detrimental to the performance of a round brilliant, but since it makes the light path less predictable, it is bound to have a negative effect. We explained it together to Jim Caudill of AGS, and I hope that he is now a motor behind figuring out the extent of that negative effect.

On the other hand, I see my dear friend Jonathan defending a point of view, based upon what he observes. Now, we can all agree that Jonathan is probably the world''s best observer of diamonds and the best criticist, but I hate to say that the best criticists are not able to produce a good movie. At this point in time, I still do not understand what Jonathan thinks he is observing when he describes yaw, but I am sure that it is something completely different from what Brian and I know to be yaw.

Correct me if I am wrong, but I think that part of the problem is due to a simplification in the courses on light behaviour in gemmolical courses. I learned what a ray of light (which is uni-dimensional) does when it hits a facet. Now, this facet is taken as a line (being uni-dimensional), while in reality, a facet is a plane, thus two-dimensional. The whole theory of light behaviour (whether a ray of light is reflected or bent) is explained in that uni-dimensional way. Now, a facet being two-dimensional, there is an infinite (nice word) number of angles on that plane. The simplification is necessary to understand what is happening with light in a gem, but everybody seems to have forgotten that there has been a simplification.

Enough for now, I did not want to stir up the commotion again. Just remember, when you were about 2, your parents told you that anyone older than 18 was a grown-up. Being your current age, do you not consider that this is not entirely the case. Does this mean that our parents lied to us? No, but we should not continue to follow their simplifications.

Live long,