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A discussion about opposite facets

Discussion in 'RockyTalky' started by stebbo, Mar 22, 2007.

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  1. stebbo
    Shiny_Rock

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    by stebbo » Mar 22, 2007
    So it''s safer to have pavilion angles in a tighter range than looser one, but if not, as long as the opposite pairs of facets are matched, we''re apparently looking ok again.

    Why?

    Maybe in Tolkowsky''s 2 dimensional world, but in 3 dimensions, only a fraction of the light might hit a facet straight on enough to be reflected to the opposite facet. Most, if not all pav. facets (even the neighboring ones) will receive the bounced rays in diffuse light, and in direct light, the diamond''s orientation will determine (and to a lesser degree the facets'' azimuths) which determine which facet gets the bounce.

    Any comments?
     
  2. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 22, 2007
    personally I don't put a ton of weight into the average theory and know of no research on it.
    On the other hand I know of no study that says how much variation is too much either.
    You can save the hearts with good averages which is likely where it comes from.


    On a related note as far as I have been able to find out no one has been able to prove that optical symmetry is more or less important than physical symmetry and if so how much(not meet point but actual tightness) so I like having both.

    There are several theories but no facts.

    This is one of those things that at least to my satisfaction no one has been able to provide solid answers.

    To me its a workmanship issue I admire the skill that goes into cutting tight stones.
    Same with EX/ID symmetry and polish and perfect hearts.
     
  3. He Scores
    Shiny_Rock

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    by He Scores » Mar 22, 2007
    Stebbo is ahead of this cut analization learning curve. My cut grading system is based on the elements AND sequence of placing facets on a diamond. The 3 criteria each facet must meet to be considered perfectly placed are in this order:

    1. Straightness
    2. Proper angle
    3. Proper depth in the girdle (with the exception of stars).

    The problem with the performance systems is that they take averages and assume that all facets are straight. Their modelling numbers will explode if they put variables in such as variations of each facet straightness and angle.

    Stebblo is also correct in that Tolkowsky''s Treatise was represented in two dimension form. That left the only thing to discuss about his theory are the top and bottom crown angles. The rest is undisputable basic mathematics.

    Stebbos pic of a performance pizza is interesting too, because its the cuttinng of a pizza pie or circle into eight equal pieces that I use to explain the mathematics of doing the same with a crown or bottom of a diamond. There''s not much wiggle room to do it successfully.

    Maybe this is why my cut grading system is the only one worthy of a U.S. Patent.

    physical symetry is where the goal of perfection lies in diamond cutting, not optical symetry where the physical symetry of the main facets is by and largely diguised.

    Go ahead. Start throwing the tomatoes.


    Bill Bray
    Diamond Cutter
     
  4. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 22, 2007
    So then why isn''t yours the standard? (not a tomato, just a jellybean!)
     
  5. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 22, 2007
    because most cutters and there for the labs don''t want too touch it with a 100 foot pole.
    one reason being is that not all rough lends itself to being cut into a perfect diamond.
    the other being as I said above no studies have been done to prove it one way or the other from a performance standpoint.
    the next being that very few cutters take the time and have the skill to cut to that level.
    As cutting technology gets better it will improve just from the standpoint of better tools.
     
  6. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 22, 2007
    what IS a perfect diamond? Seriously... a perfect diamond to me and a perfect diamond to you are NOT even the same cut! Let alone a "perfect" round LOL

    BTW all rough lends itself to being cut into a "perfect" diamond IF you''re willing to have a lot of waste ;) And by perfect, we mean rounds right? They''re the only perfect stones (TIC).
     
  7. He Scores
    Shiny_Rock

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    by He Scores » Mar 22, 2007
    Cehra...


    Cehra...

    Several things I suppose. I''m a little guy and didn''t market it thoroughly. Second, the labs were lobbied heavily by the performance manufacturers/sellers. The measuring machine mfgs. thought that since my approach was contrary to what their big labs/customers used it would be political suicide to work with my system.

    Storm''s correct on some points, however, it''s not hard to cut to achieve relatively high scores in the 900+ range. As far as the research goes, it seems to me that the non-acceptance of the patterning by the trade and also the small sampling that I did along with the inconclusive GIA observations tests indicate that physical symetry and optical symetry are two distinct entities and not necessarily connected to each other. As far as being "tested", the Tolkowsky model has over 85 years of market share. My system uses the Tolkowsky model (in general) as the basis for a "perfect" stone and then the deductions for targets missed are taken into account.


    I think in time, the trade will realize this and hopefully I''ll be the only one on the physical symetry/measurement analysis side of the fence.


    Bill Bray
    Diamond Cutter
     
  8. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 22, 2007
    so you just deal with rounds?

    I''ve been trying to figure out the angles on my stone... I got a sarin but of course the info thinks it is a really bad round so I really can''t even decipher it... but in person and in photos I can see how in particular the largest of the pav facets interacts with its corresponding crown(kite) facet. They DEFINITELY use each other like a periscope or something and what comes out of that crown facet is *always* a refraction. Now, when I''ve looked at garry''s HCA and followed the path beyond his graph to where my crown and pav are, it seems like it would still be in the red zone, or at least orange... definitely not out in the blue area... and so I tend to think that my facets ARE working well together even though they are like 37/38 pav and 39/40 crown (aprox - I''m really not sure because the sarin info is whack to my eyes).

    now, in my head I think garry is right in that the two angles have to work together and that depending on where you want the light to go and come from will play a roll in what those angles should be like, not just in relation to one another. My stone does NOT send out a white round beacon, but it does a fantastic job of sending out a rainbow of rainbows. The aset is about 50% green, 40% red, 5% blue and 5% black (leakage). I feel like it does such fabulous things... I''ve compared it to AGS000 stones and they''re just different, but one is not better... the AGS rounds sock a more powerful punch and provide a more clear outline of white return, but my stone looks better from more angles and has much more going on with color both from reflection as well as refraction. My gripe is that there is nothing *wrong* with these superideals, but they''re only showing one story. I feel like I''m constantly arguing with John about the color GREEN lol And it makes it seem like I don''t like the superideal ASET RED rounds (IMO I''d choose nothing else for a pendant) but its not true. I just see EVERYONE championing this superideal idea and NO ONE is stopping and saying, you know, other combos of angles look fantastic in other ways too. Maybe the new AGS thing is gonna do that! But I still think people are going to (out of fear of making a huge mistake and ending up with a dud) gonna stick with some fairly tight parameters instead of saying okay lets see if we can make an AGS000 with a 50 table, a 40 crown angle and let''s see... ::does calculations:; and the corresponding pav angle is (fill in the blank) and let''s do this and see what this stone can do! Bah... now I''m rambling and my point is lost... hopefully someone can find it LOL
     
  9. He Scores
    Shiny_Rock

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    by He Scores » Mar 22, 2007
    Cehra...right now my patent only covers rounds. However, the basis for it is the same as the basis for cutting a diamond so my formulas could be expanded to each fancy shape with the appropriate testing. Since it took seven years to get my initial formula fine tuned to where I felt it fit with the day to day usage of buying and selling diamonds, I'm in no hurry to go to each particular fancy shape and do it again until this one becomes revenue producing.

    As far as "looking" at a diamond, no two people will ever see the same thing and looking at a diamond with the neked eye to determine the quality of cut is tantamount to looking at the front of a house and determing whether it's built well or not.

    However, while there are pundits who think it will help the tradesman if the parameters of a well made stone are expanded (a false notion I might add), most cutters of even the premium cuts agree to the angle measurements that were handed down by Marcel Tolkowsky. While the "face up" light return MAY be very similar if these angles are fudged, there are other factors of viewing the diamond that will change. It's these changes that the trade by and large will not accept as being a premium cut stone. Shallow crown and pav angles, small tables all exhibit a view of this three dimensional object that haven't stood up to market review.

    Viewing the light return of a diamond and then classifying cut is a quantum leap of huge proportions IMHO. In mathematics, there's a saying that says, "the best laid theories are laid to rest by one insignificant fact". I once asked Bill Boyajian of the GIA...."when can you have a perfectly done ideal cut diamond and no brilliance?" He couldn't answer the question. The answer is an opaque color. Thiis is the obvious inconvenient fact that should lay to rest that a good performing stone is a good cut stone. Physical symetry and optical symetry are two different entities. While I won't argue the need for examing how well a stone performs in certain light etc., there still needs to be a quantification of the physical symetry to round out the picture. That's' what my system is all about.


    Bill
     
  10. boston_jeff
    Brilliant_Rock

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    by boston_jeff » Mar 22, 2007
    I''m not sure what this means. If the only answer is "an opaque color," then isn''t an easy solution to just look at ideal cut diamonds and then rule out opaque color? Maybe I''m missing something, but that "inconvenient fact" seems to show that "a good cut stone is not necessarily a good performing stone," not that "a good performing stone is not a good cut stone," as you claim.
     
  11. stebbo
    Shiny_Rock

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    by stebbo » Mar 22, 2007
    The way I see it, a diamond''s standout RI means its role in the world is to concentrate light or separate light (or a bit of both). If you''re concentrating light, you want to do it as quickly as possible to limit attentuation and dispersion. That requires as few clean bounces as possible. Given that we''re dealing with an organic substance, geometrical symmetry (including tightness) and precise meet points etc can only be starting points, not goals. Optical symmetry (true optical symmetry, not just H&A) must be key. But having said that, how much brighter is an 8* anyway?

    I know you''re a fan of workmanship, but wouldn''t you agree that it takes more skill to work an organic substance to maximum optical efficiency than just to geometric precision?
     
  12. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 22, 2007
    stebbo its not that easy....

    The goal isnt maximum light return its a pretty diamond.(doing that while returning as much light as possible is how ever a good goal.)
    Get DC and start designing diamonds.
    Get the most red you can in the ASET view eliminate all the blue and green you can.
    Then play it in the video modes, it looks like caca when compared to a more balanced diamond.

    Also try and design a diamond with no color light return.. if it has facets it cant be done.
    Most of the visible fire in RB diamonds is returned around facet junctions because that is where the biggest seperation occurs. At or near the facet junctions.
    Study B-scope images and see where the colored light is coming from.

    The best optical symmetry is achived when the light paths for a beam striking any given point is the same path pattern and distance for any of 8 identical points on the diamond.
    Do that without physical symmetry on an 8 fold symmetry object and report back.
     
  13. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 22, 2007
    The answer to the 8* question is brighter than some not as bright as others.
    The same could be said of any well cut diamond, see the second line of my above post in this thread.
     
  14. He Scores
    Shiny_Rock

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    by He Scores » Mar 23, 2007
    Boston Jeff,
    It can go both ways primarily because how a stone "performs" (defined as how it looks either to the neked eye or by magnification) depends on other factors other than cut. Finish, material, grain, clarity, color are all factors that affect how a diamond looks. So what I''m saying is that how a diamond "looks" doesn''t always point to the cut. You can have a better looking stone that''s cut less well than a poorly performing stone that cut precisely.

    Speaking of which, when we are talking about how an 8* looks, I''d like to point out that a logical extension of my cut analysis sytem would entail compensation for stones of varying color. Not all material is destined to be cut to "ideal" proportions. Some stones will face up better with shallow angles and some not. These are decisions that the cutter makes at the outset of planning the stone. Cut analysis needs to be kept in context with that and other everyday decisions in the commerce of diamonds. Making it too complex only aids those whose charge it is to study it and hinders others whose livelyhood depends on other aspects of the diamond business other than studying cut.

    Bill
     
  15. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    here is a virtual stone cut for max light return with every trick in the book thrown at it to eliminate blue and greens.
    it even has pavilion painting *puke*

    open it in GemAdvisor and check it out.... its bright but its also fugly.

    I call it the star and dagger cut (copyright reserved)
     
  16. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    Here is my wifey2b''s to compare it too...
     
    • w2b.gem
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  17. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 23, 2007
    hers is MUCH nicer! Hey - can I see your dream asscher? What else you got over there? I need DC hahaha (riiiight like my dh would handle any more diamond addiction LOL W2B is lucky indeed!!)
     
  18. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    I call this one the monster.
    I designed it before I had aset in DC so it isnt the best looking in aset but hit play (green arrow) and you will understand but some wont.
     
  19. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    some numbers.....
    edit: id also eliminate the 3rd crown step and make it a 2 step which is why the first step is so small.

    monster.JPG
     
  20. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    Here is the monster2 at 79.3% depth and a 3 step crown same 27.8 table, 27.5 crown height. 1.03ct
    Which is a 10 minute edit of the monster.

    I also have some designs under 50% in depth but I wont post the gem files for them.
     
  21. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 23, 2007
    I have to dl these on my other computer later (we''re watching casino royale so I''m on laptop) but I had to ask out of curiosity.... why won''t you post the gem files for those under 50?
     
  22. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 23, 2007
    someone could get all the data from the gem file needed to cut them.
     
  23. Garry H (Cut Nut)
    Super_Ideal_Rock
    Trade

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    by Garry H (Cut Nut) » Mar 24, 2007
    Some problems Stebbo:

    1. your logic is founded on light being a ray format. But most of the time we see a diamond the light is behaving as a beam because it is coming from a small glabe and radiating, or a large window from many directions at once etc
    2. The assumption is that if the light "misses" the opposing reflector that it is lost. This is wrong.
    3. The idea that there are bigger flashes is good (based on roiund brilliants) is wrong because there are many cuts where a smaller flash is desired - eg princess cuts have much smaller flashes and some peple prefer that, Asschers have fewer and bigger and others prefer that.
    4. our eyes, the ambient brightness and pupil diameter, the background the diamond is seen from - all these things have an impact on what we see and introduce variables way beyond your nice simplification.
     
  24. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 24, 2007
    I kind of assumed that, but what is your fear there? I mean the only people who can cut them are cutters but a) would they really want to? and b) what is the harm if they did? also c) couldn''t they come up with it on their own?

    I''m honestly not trying to coerce you, just curious!
     
  25. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 25, 2007
    a: they would sell very well if someone could find rough to cut them from.
    b: dunno, if someone asked id send them to them.
    c: after spending several hundred hours sure.

    I guess at this point they are just something I want to play with for myself and maybe someday have one cut.
     
  26. Cehrabehra
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    by Cehrabehra » Mar 25, 2007
    have a shallow one cut, not your dream stone? I''m going to dl these now.. I''m on the right computer! I''ve been playing with W2B''s stone and mine the last couple days...
     
  27. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 25, 2007
    I like M2 better than M1. And it is gorgeous... hugely bulging... what is the diameter?
     
  28. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 25, 2007
    same as m1
    5.54

    Id like both cut actualy all 3 a 50%er and m1 and m2 cuz I think in real life m1 would give m2 a run for its money if not kick its fanny.
    cut em out of a chunk of O or P rough and they would be yummy.
     
  29. Cehrabehra
    Super_Ideal_Rock

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    by Cehrabehra » Mar 25, 2007
    I love those colors... LMNOP :) I''m really surprised you''d love a stone that shallow though... be way cheaper to have custom cut for sure LOL (for the diameter)
     
  30. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Mar 25, 2007
    Whats not too love? 49.9% depth asscher.
    not the best aset but everything else looks kewl
     
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