noobie
Brilliant_Rock
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GEMEX Accurate Science or Smoke & Mirrors
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wonka27
Brilliant_Rock
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It is then further stated in this article...
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Researchers determined many proportion combinations yielded above-average DCLR values, while others clearly showed lower values. One surprising finding: Lengthening lower girdle facets in relation to the lengths of the standard reference stone yielded greater DCLR. GIA points out that previous studies and most cut grading systems ignore the dramatic effects observed when lengthening or shortening these facets.[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular](emphasis mine)[/FONT]
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]My question SuperIdealist ... do you agree with the facts and conclusions of GIA's findings or do you not?
[/FONT]
JohnQuixote
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Hello fellows!
I've been out for a few days (or - I just returned from elsewhere and am glad to be somewhere again!!)
Nice to see this topic still brewing.
RhinoKnight: That article you cite is almost 3 years old and not completely up-to-date. It is generally known within the trade and amongst scientists that what was stated in that article by GIA was scientifically unsound.
If you were at the Basel show, before the International Cut Conference in Moscow, GIA advised people of what was going to happen in the cut grade system. Some of that more recent information, especially as it pertains to lower girdle facets, will be pertinent to further discussion about your assertations... Did you know, for instance, that there are plans for diamonds with lower girdle halves >80% to be downgraded?
Garry addressed some of this info before, in this thread.
The way this topic is developing, we may need another thread, as we switch to a conversation of facet construction and how it relates to BS error.
Much more later!
I've been out for a few days (or - I just returned from elsewhere and am glad to be somewhere again!!)
Nice to see this topic still brewing.
RhinoKnight: That article you cite is almost 3 years old and not completely up-to-date. It is generally known within the trade and amongst scientists that what was stated in that article by GIA was scientifically unsound.
If you were at the Basel show, before the International Cut Conference in Moscow, GIA advised people of what was going to happen in the cut grade system. Some of that more recent information, especially as it pertains to lower girdle facets, will be pertinent to further discussion about your assertations... Did you know, for instance, that there are plans for diamonds with lower girdle halves >80% to be downgraded?
Garry addressed some of this info before, in this thread.
The way this topic is developing, we may need another thread, as we switch to a conversation of facet construction and how it relates to BS error.
Much more later!
Superidealist
Brilliant_Rock
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The example you cite does show that DCLR increases with increasing lower-girdle facet length (up to about 85%) but this result assumes a crown angle of 34 degrees, a pavilion angle of 40.5 degrees, a table size of 56%, a star facet length of 50%, a girdle thickness of 3%, a culet size of 0.5% and a faceted girdle having exactly 64 facets. So, yes, for such an incredibly specific type of diamond, I agree with you, however, changing any of these other factors may affect the relation of DCLR and lower-girdle facet length.
I would say that variation in DCLR with different proportion combinations prevents the simple characterization of the "best" diamonds, in terms of fire, by evaluation of individual proportion parameters. It seems to me that it is the interaction between the proportions of the pavilion (pavilion angle and lower-girdle facet length) and of the crown (table size, crown angle, and star facet length) that determines how light is dispersed by a diamond. Although certain generalizations may be made about the effects of a single proportion (such as lower-girdle facet length), in most cases, there exist combinations of proportions that compensate.
Now that we have that out of the way, where is your proof that the BrillianceScope correctly measures, say, scintillation?
I would say that variation in DCLR with different proportion combinations prevents the simple characterization of the "best" diamonds, in terms of fire, by evaluation of individual proportion parameters. It seems to me that it is the interaction between the proportions of the pavilion (pavilion angle and lower-girdle facet length) and of the crown (table size, crown angle, and star facet length) that determines how light is dispersed by a diamond. Although certain generalizations may be made about the effects of a single proportion (such as lower-girdle facet length), in most cases, there exist combinations of proportions that compensate.
Now that we have that out of the way, where is your proof that the BrillianceScope correctly measures, say, scintillation?
wonka27
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niceice
Brilliant_Rock
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On 10/5/2004 2:18:57 AM Blueman33 wrote:
How silly of us to think that we could say something relevant to the topic at hand on an open forum without an invitation... What were we thinking? Hey Leonid, could we "please" be retroactively invited to partake in this discussion so that our previous commentary can be determined as acceptable to the other readers of this forum?
Who requested the information? We made that clear in the first line of our post Blue - it was a question posed to us via private email from somebody here on the forum who had the tact not to ask us directly on the thread in case we weren't ready to address the issue publicly. The fact that you referenced our indication of the question being posed via private email in the first line of your post seems like sufficient data enough for you to have answered your first question all by yourself.
You are entitled to your opinion of course and if you don't like our literary style, you should purchase your diamond from somebody else. In our experience sales are most successful when people have a common ground, mutual interests and have developed some sort of relationship. Many people here on PS happen to like us, respect our opinion and buy from us as a result. How do we know that "Many people" think that? Well, not because we're arrogant, but rather because they take the time to tell us so here on the forum, via email, or on the telephone when they buy a diamond from us...
How do we know that a lot of people were waiting for us to say something brilliant about the Bscope? Because we've received a lot of email and private messages asking us if we were going to make statements to that effect. Rather than continue to answer each of those questions one by one or have people start to ask us to do so here on the forum as they have in the past on certain posts we took the initiative to say that we wouldn't be doing so and explained why - due to contractual limitations.
With a hundred or so posts under your belt, we suppose that you are not familiar with the fact that we have long been known here on PS and on every other diamond forum for being a MAJOR opponent of the Bscope and its use by independent vendors as a sales tool. If you want to attack us and it appears that you do, why not attack us for something valid like changing our opinion on a piece of equipment halfway through the battle? We would have been executed for that during the civil war and that at least would be interesting.
Now we have to say, we "really" like the "excuse me while I vomit" crack, in fact, we're sure that "everybody" did. We "know so" because several of them have begun to tell you so. But what they may not realize is that we "really" do think that the concept is funny, you sitting there at your computer trying to type with vomit spewing out all over your screen and down your shirt and down on to your shoes and all because of something so simple said by little ol' us.
Hope you can read between the chunks... Have a great day.
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On 10/5/2004 9:09:04 PM Superidealist wrote:
The example you cite does show that DCLR increases with increasing lower-girdle facet length (up to about 85%) but this result assumes a crown angle of 34 degrees, a pavilion angle of 40.5 degrees, a table size of 56%, a star facet length of 50%, a girdle thickness of 3%, a culet size of 0.5% and a faceted girdle having exactly 64 facets. So, yes, for such an incredibly specific type of diamond, I agree with you, however, changing any of these other factors may affect the relation of DCLR and lower-girdle facet length.
So you are saying that DCLR is increased *only* in diamonds with those specific dimensions? I thought we could think more outside the box but I do not believe GIA's intent was limited to only stones with those proportions. For example those of us within the trade know that increasing a crown angle from 34.0 to 34.3 has no great bearing on light performance. Neither does changing the angle from 40.5 to 40.6. What I am talking about is more serious changes, ie. the lower girdle facet length. I realize you are a consumer and do not work with diamonds or optical technologies on a regular basis so if your thinking can only expand to the point of what GIA says or doen't say I understand that and realize that this conversation can go no further. As Valeria points out in her signature ... "The greatest experts are only as good as the sum total of what they have seen." I make it my business to understand what it is I'm selling and talking about and if there are concepts about light return, the strength at which it is reflected back to the eye etc. as it is shown not only in B'scope results, red reflectors, etc. that you do not grasp that's ok.
You see SI, when GIA comes out with a statement that DCLR increases as lower girdle facet length increases... I make it my business to understand *why* and not just accept at face value. Do you really understand why DCLR increases as lower girdle facet length increases, even if we want to stick to the one model of 34/40.5/56 with stars of 50 and lower girdles of 75%? If you don't I'll be more than happy to teach and demonstrate.
I would say that variation in DCLR with different proportion combinations prevents the simple characterization of the 'best' diamonds, in terms of fire, by evaluation of individual proportion parameters. It seems to me that it is the interaction between the proportions of the pavilion (pavilion angle and lower-girdle facet length) and of the crown (table size, crown angle, and star facet length) that determines how light is dispersed by a diamond. Although certain generalizations may be made about the effects of a single proportion (such as lower-girdle facet length), in most cases, there exist combinations of proportions that compensate.
I agree. If we take a diamond with say ... 36 crown angles, 41.5 pavilion angles, 60 table ... there isn't much we can do that'll help such a stone because those angles would be causing the lower girdles to function as windows as opposed to mirrors.
My statements can only be construed or make sense when the lower girdles are functioning as mirrors and not windows. (For the readers... if facets are functioning as windows that means light is passing through them as opposed to reflecting off of them).
Now that we have that out of the way, where is your proof that the BrillianceScope correctly measures, say, scintillation?
SI... the answer to your question can be answered with another very simple question.
What was Tolkowski's proof that 34.5/40.7/54 was the most brilliant? Tolkowski was not a scientist when he wrote "Diamond Design". He was merelly a college student writing a thesis. What was his proof? Who knows the answer to this question?
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Superidealist
Brilliant_Rock
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I think I'd prefer to leave the science of this to the real scientists, Jon. It would be presumptuous of amateurs like us to overgeneralize.
I agree with this point completely, but where you run afoul of me is when you treat these works in progress as if they were the final word. The BrillianceScope has not yet been shown to accurately measure what you claim. For the statements you made earlier to qualify as fact, the BrillianceScope would need to udergo the kind of rigorous testing JohnQuixote has recommended. Until then, it's simply your opinion.
P.S.
I would have preferred that you answer it with an answer, but I do get your point (or what I think is your point). Tolkowsky's "proof" while not precisely correct was the best that could be done at the time and had the effect of changing diamond cut for the better. Technologies such as the BrillianceScope, Firescope, and the computer models being done by GIA, MSU, and others also may not be precisely correct but are currently the best we can do and are having the effect of increasing diamond cut quality.
I agree with this point completely, but where you run afoul of me is when you treat these works in progress as if they were the final word. The BrillianceScope has not yet been shown to accurately measure what you claim. For the statements you made earlier to qualify as fact, the BrillianceScope would need to udergo the kind of rigorous testing JohnQuixote has recommended. Until then, it's simply your opinion.
P.S.
I was disappointed to see you agree, since I had lifted this statement almost word for word from the GIA fire study. I was hoping you'd take the bait.
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On 10/5/2004 10:47:05 PM wonka27 wrote:
Rhino -
This is to the point where I have no clue as to what you guys are talking about
Irregardless of what equipment you use, pricescopers know that you sell fantastic goods! I think it is great you have something that can help the consumer make a selection though!
You da man, dawg!
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LOL... thanks man. Didn't mean to take it over the top. One reason for my bringing up the GIA study Wonka is because GIA has arrived at the same conclusions I have although we've taken different roads to get there. One conclusion of my studies on the minor facets is that when you take diamonds cut to certain proportions (where you are causing the facets to act as reflectors instead of windows), if you take the lower girdles and lengthen them this increases the diamonds total brilliance in direct light conditions. GIA is calling it DCLR or in short ... fire. Fire is best observed in the light conditions GIA was testing it under which is a direct light source. If we were to seperate the components of fire and scintillation I would also emphatically state that it impacts scintillation as well. My studies on this subject are covered in our chapters on cut particularly in the section on the "minor facets" and also "firescope/idealscope" where we show the correlation between the 2 technologies (Red reflectors/B'scope). Besides my own God given set of eyes, the BrillianceScope is a tool that has also showed me this truth. If it was a misleading technology I would not have arrived at those same conclusions. If my conclusions were different I would have to seriously reassess what it was the B'scope was teaching me with regards to what it is reporting.
BTW ... I'm not here arguing the infallibility of the technology either so I will not be backed into that corner. There are issues with it but if a person is going to criticize it, let them at least be familiar with it and address those issues independantly. Not just come here and say the B'scope is not good becuase I don't think it's good or because it disagrees with my personal preference. I just showed a diamond to a person who said it was the most scintillating diamond they've ever seen (Eighternity), when asked if you had to choose between that and another we were comparing it to (an H&A) they personally preferred the H&A. When asked why, they exclaimed that the one was a little too busy for them while they preferred the larger splashes coming from the H&A. Another person I showed the same 2 stones too would not do without the Eighternity and preferred the spray of many tiny shards of light mixed with fire they observed in that stone.
Is one more beautiful than the other? No. Each is a matter of preference although one diamond was clearly more scintillating and the client knew this up front. This is what I mean about seperating facts from preference.
SI... let's assume for a moment that you purchased a diamond with 34/40.5/56/50stars/75% lower girdles ... and we know for a fact that increasing it's lower girdle length to 79% will inrease the diamonds overall brilliance (I would add in direct light conditions) or DCLR ... I would gamble and say that you probably still would prefer the look of the shorter lower girdle length. Would this be a correct statement?
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On 10/6/2004 2:54:57 PM Rhino wrote:
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On 10/5/2004 10:47:05 PM wonka27 wrote:
Rhino -
This is to the point where I have no clue as to what you guys are talking about
Irregardless of what equipment you use, pricescopers know that you sell fantastic goods! I think it is great you have something that can help the consumer make a selection though!
You da man, dawg!
----------------
SI... let's assume for a moment that you purchased a diamond with 34/40.5/56/50stars/75% lower girdles ... and we know for a fact that increasing it's lower girdle length to 79% will inrease the diamonds overall brilliance (I would add in direct light conditions) or DCLR ... I would gamble and say that you probably still would prefer the look of the shorter lower girdle length. Would this be a correct statement?
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re
CLR showed dramatic increases as lower girdle facets increased in length 45%-85%. Hi Rhino,
Did you read part of my discussion with Marty concerning LF and Fire?
https://www.pricescope.com/community/threads/ags-new-cut-grade-system-early-2005.19268/page-3
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Hey Serg,
I can see you guys are discussing similar things in that thread. I generally avoid these 4 page threads but I see I'm going to have to read all of that. I'll need to catchup on my emails first but you can bet I'll be all ears/eyes as I'm reading there. I am extremely interested to read about your discoveries regarding lower facet length and it's impact on diamond optics.
I can see you guys are discussing similar things in that thread. I generally avoid these 4 page threads but I see I'm going to have to read all of that. I'll need to catchup on my emails first but you can bet I'll be all ears/eyes as I'm reading there. I am extremely interested to read about your discoveries regarding lower facet length and it's impact on diamond optics.
niceice
Brilliant_Rock
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On 10/7/2004 7:33:03 PM Blueman33 wrote:
No worries, those who know us realize that it's all taken in stride...
We have PLENTY to say on the subject of the Bscope! Here we go again... EVERYBODY who knows us knows that!
However we made a choice... And that choice was to shut-up (and that's not easy for us) so that we could provide Bscope results to our customers who were asking for them AND we are restricted by contract from discussing how the Bscope works or providing comparisons between the Bscope and other "comparable" devices, etc.
At this point in the game, it really isn't important whether we think that the technology is accurate or not. We decided to provide the scan results because a majority of our on-line customers were requesting the information. We are aware of several other on-line dealers who have also added the device to their evaluation process or will be during the next few weeks. It really isn't a matter of whether the machine is accurate or inaccurate, it is a matter of consumer demand. Gem Ex has done an excellent job of marketing their product to the on-line community as has Jonathan at GOG and the reality is that it is a practical necessity for selling diamonds on-line at this point in the game. We're hoping to be as impressed as Jonathan is with his machine, the fact of the matter is that we haven't had ours long enough to make a determination to that regard. But the reality is that whether we are or aren't, we aren't allowed to discuss that fact so we won't. And that is the long explanation to our short and sweet "arrogant" statement made previously.
Superidealist
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