Reflected / Refracted light? Scintillation / Fire / Brilliance

[klavigne]

When people are talking about Scintillation what exactly are they talking about. Is it reflected light or refracted light? If it is reflected light then the polish of the facets would be very important to scintillation, correct? And if this is correct then to maximize fire and brilliance then you need to have a stone with ideal polish, correct? Or is the brilliance of a stone based more on the symetry and proportions of hte stone and not related to scintillation at all? Im confused again!

 

[klavigne]

I''d like to hear from Garry or David on this, so I''m bumping it in hopes they will see it.

 

[Rhino]

Well ... not as handsome or debonaire as Garry or Dave but ...

Date: 4/6/2006 10:42:42 AM
Author:klavigne
When people are talking about Scintillation what exactly are they talking about. Is it reflected light or refracted light? If it is reflected light then the polish of the facets would be very important to scintillation, correct? And if this is correct then to maximize fire and brilliance then you need to have a stone with ideal polish, correct? Or is the brilliance of a stone based more on the symetry and proportions of hte stone and not related to scintillation at all? Im confused again!

In a nutshell ... Scintillation is simply the observance of the movement of both white and colored light within a diamond when either the

a. observer is moving
b. the diamond is moving
c. the light source is moving
d. all of the above (like when or if you''re drunk, at least they all seem to be sometimes)

This light is both reflected and refracted since when a person looks at a diamond they are going to see both.

Polish and symmetry play a role in this but polish to a lesser degree which is why GIA includes the "very good" rating for polish & symmetry among their "excellent" cut grades. This was a good and proper admission by the GIA regarding how slight if at all the difference between excellent/ideal polish has bearing on the optical performance of a diamond.

Scintillation is a tough beast to nail down as there are different personalities that comprise what folks feel is more attractive. For example in round brilliant cut diamonds you can have stones which place an emphasis on broad flash, while there are rounds that have an excellent mix of both broad flash mixed with pin flash, and then there are stones which emphasize pin flash.

What a person prefers at that point boils down to a matter of taste or personal preference.

These same nuances in scintillation can also be seen amongst certain superior crafted squares as well.

HOpe that helps.

Jonathan

 

[klavigne]

Scintillation is a tough beast to nail down as there are different personalities that comprise what folks feel is more attractive. For example in round brilliant cut diamonds you can have stones which place an emphasis on broad flash, while there are rounds that have an excellent mix of both broad flash mixed with pin flash, and then there are stones which emphasize pin flash.


Okay John,
So what your talking about is the differences in a FIC, BIC & TIC stone. But I thought those were all based on crown/pav angles, along with table percentages. So as I understand it then, a solasfera stone will have more fire than a traditional 58 facet round, which would have more broad flashes of white light? And that would be because of the solasfera having more small facets.
Also, then refracted light and reflected light both play parts in scintillation, so wouldn''t a more highly polished light "throw" off more reflected light, which would be whiter than the light that is allowed into the stone to bounce around and be dispersed (sp?). Does the angle of incidence have anything to do with this as you stated, head/light/stone moving?
If all of this is correct, then it would seem to also be correct that a stone with an ideal polish would have more broad white flashes (brilliance) than small colored flashes (fire)? So if I''m looking for a stone with more fire then a stone with less than ideal polish would be a better bet? I''m really trying hard to understand all of this but it seems so subjective, Any help is very appreciated. Thanks again!

 

[oldminer]

I like Jonathan's response. It shows the complexity of what the word stands for. In simple terms, if you had a mirror you'd have high light return from reflection and no scintillation. Break the mirror into bits and mount them on a flat board at slightly varying angles, not all flat to the board, and you'd get scintillation of light as you went past the board. There'd be lots of momentary bright flashes.

Depending on the size of the mirror particles, the direction of the illumination and the strength of the light, the amount of scintillation would vary. Old cut diamonds have an appearance of larger mirror parts. Modern cut diamonds have the appearance of smaller, more needle-like mirror parts. Branded diamonds, those with extra facets, may have smaller sparkly areas because they have more facets. Symmetrical stones have more even patterns than less symmetric stones.

Again, it is a matter of personal taste. It also is a matter of "appreciation". You may develop more sense of beauty and its judgment over time. The more you know about the subject, the more discerning you may become. Especially if you don't mind paying more money for what is generally considered "better".

 

[valeria101]

Date: 4/6/2006 10:42:42 AM
Author:klavigne

When people are talking about Scintillation what exactly are they talking about. Is it reflected light or refracted light?

''Guess every post here talks about refracted light. You''d hardly find one word about surface reflection in the HUGE stash about cut grading... and quite reasonably so, IMO.

I am not sure if different grades of polish really make any difference, since the tiny eye-crossing ''flaws'' that make the cut between ''Good'' and higher grades of polish achieved by modern equipment are localized, not affecting the polish throughout (as in ''good'' is overall rougher polish than ''ideal'' - there may be an obscure grain line to make the difference, or something like that).

As far as I know.

 

[klavigne]

So let me ask this then; How does one go about making a stone have more fire than brilliance? How is it measured by the labs? It''s not like I could take a bunch of stones, shine a light at them and measure the spectral return and say this one has a broader spectrum so it must have less fire. If I used a spectrometer to measure this it really wouldn''t tell me much about the overall light return, it would just tell me what region of the light it was.
I''m really trying to understand the subject, but the amount of knowledge out there is very, very limited to the average Joe. It all seems so subjective that there almost isn''t a right or wrong answer. But if I read an AGS report and it tells me that the light performance is zero, how do they get that number is what I want to know.

 

[Rhino]

Hi klavigne,

Between the lines...

Date: 4/6/2006 2:27:26 PM
Author: klavigne
Scintillation is a tough beast to nail down as there are different personalities that comprise what folks feel is more attractive. For example in round brilliant cut diamonds you can have stones which place an emphasis on broad flash, while there are rounds that have an excellent mix of both broad flash mixed with pin flash, and then there are stones which emphasize pin flash.


Okay John,
So what your talking about is the differences in a FIC, BIC & TIC stone. But I thought those were all based on crown/pav angles, along with table percentages.

Nope. Garry''s FIC, BIC and TIC are exactly as you describe ... based solely on table/crown/pavilion angles. Broad flash vs pin flash or a combo of the 2 requires a knowledge of lower girdle facet & star facet length and upper girdle angles. Since the HCA does not take these facet measurements into account, it is my professional opinion that the scintillation measurement on the HCA is not a good thing to use as an indicator to determine the nature or type of scintillation a person is looking for. I can show you 2 diamonds that have identical scintillation readings on the HCA (with similar crown/pavilion/table data) that vary dramatically in their scintillation and appearance. BIC, FIC and TIC have nothing to do with it.

So as I understand it then, a solasfera stone will have more fire than a traditional 58 facet round, which would have more broad flashes of white light? And that would be because of the solasfera having more small facets.

More fire may be a matter of interpretation as the Solasfera''s definitely vary in appearance from ideal cut 57 facet round brilliants in lighting that induces fire. Many people who view the comparison do indeed interpret it that way, but personal preference doesn''t always lie with that appearance. There are many who prefer the other appearance as found in 57 facet ideal cuts. It would be accurate to say that a Solasfera exhibits a greater amount of pin flash with broadflash though than an H&A round. We recently published a video showing this very phenomena. I''d say it''s been a pretty even split so far for people who have seen both types.

Also, then refracted light and reflected light both play parts in scintillation, so wouldn''t a more highly polished light ''throw'' off more reflected light, which would be whiter than the light that is allowed into the stone to bounce around and be dispersed (sp?). Does the angle of incidence have anything to do with this as you stated, head/light/stone moving?

A highly polished diamond will not necessarily throw off more reflected light. Really ... any flat polished surface of the diamond will throw off reflected light. The polish on a diamond affects moreso the sheen on the facets surface and does to a degree impact reflected light. If we were to think about this on a more magnified scale klavigne let''s use the example of a car.

If we take a car and wax and polish the front side panel and leave the door panel unpolished, when the sun hits it you will see a glossy sheen and sharp reflection of light off of the polished portion of the car. (heh... reminds me I need to wax my car!

) now we can still see the reflection of light off of the part of the car that was not polished but the nature of the reflection of light off of each part is different. Now reduce that down to diamond size.

If all of this is correct, then it would seem to also be correct that a stone with an ideal polish would have more broad white flashes (brilliance) than small colored flashes (fire)? So if I''m looking for a stone with more fire then a stone with less than ideal polish would be a better bet? I''m really trying hard to understand all of this but it seems so subjective, Any help is very appreciated. Thanks again!

It''s a pleasure to help k. My suggestion is this ... when looking at diamonds whether the polish is very good or excellent is moot really especially when if only 1 or 2 facets does not adhere to "excellent" polish it is downgraded to "very good".

What you may want to determine on a personal level is if you prefer ...
a. An emphasis on broadfire flash.
b. An empahsis on mix of broadfire plus pin flash.
c. An emphasis on pin flash.

There are diamonds that cover these varying appearances. A knowledge of all the facets are required though and analysis, at the very least of a 3d model. I can demonstrate these differences for you if you like.

Kind regards,

 

[Rhino]

Date: 4/6/2006 3:03:20 PM
Author: oldminer
I like Jonathan''s response. It shows the complexity of what the word stands for. In simple terms, if you had a mirror you''d have high light return from reflection and no scintillation. Break the mirror into bits and mount them on a flat board at slightly varying angles, not all flat to the board, and you''d get scintillation of light as you went pst the board. There''d be lots of momentary bright flashes.

Depending on the size of the mirror particles, the direction of the illumination and the strength of the light, the amount of scintillation would vary. Old cut diamonds have an appearance of larger mirror parts. Modern cut diamonds have the appearance of smaller, more needle-like mirror parts. Branded diamonds, those with extra facets, may have smaller sparkly areas because they have more facets. Symmetrical stones have more even patterns than less symmetric stones.

Again, it is a matter of personal taste. It also is a matter of ''appreciation''. You may develop more sense of beauty and its judgment over time. The more you know about the subject, the more discerning you may become. Especially if you don''t mind paying more money for what is generally considered ''better''.

Excellently said Dave. In modern round brilliants, I find those with the short lower half lengths, short stars and small tables to mimic best the appearance of the older cuts. We recently took in an old euro that displays the chunky mirror effect. Hope this post finds you and your crew well.

 

[Rhino]

Hey Val!

Yea ... many conversations center around refracted light or internal reflections. I myself often neglect the external reflections when speaking on the subject.

All the best,

 

[Rhino]

Date: 4/6/2006 3:29:02 PM
Author: klavigne
So let me ask this then; How does one go about making a stone have more fire than brilliance?

You do not have to sacrifice brightness (brilliance) for fire. The observance of brightness and fire are determined by the lighting environment you are viewing the diamond in. A general rule of thumb is this ... the stronger the lighting environment the more the diamond should function as a prism. When you diffuse or soften that lighting, the less you will observe fire and the more you will observe brightness. There are also environments wherein both brightness and fire can be observed as well.

How is it measured by the labs? It''s not like I could take a bunch of stones, shine a light at them and measure the spectral return and say this one has a broader spectrum so it must have less fire. If I used a spectrometer to measure this it really wouldn''t tell me much about the overall light return, it would just tell me what region of the light it was.

There are technologies which accurately portray diamond appearance in varying light conditions. I am familiar and work intimately with each of these on a daily basis. As far as being measured by the labs, the 2 most conservative labs employ different methodologies in determing their top cut grades. AGS for example employs the use of the ASET Reflector (angular spectrum evaluation tool) and GIA employs observation testing under diffuse fluorescent lighting for brightness/scintillation and direct led lighting for fire/scintillation. So AGS is looking for certain "reflector images" while GIA is looking for a certain minimum appearance in brightness/fire/scintillation" as their graders look at the stones. Both systems are excellent and each of these labs have the best interests of the consumer in mind.

I would also point out that the top cut grades from each of these labs cover varying appearances which some may prefer over others. In both systems lower girdle length can vary from as low as 70% and as high as 85%. This one variation in this one facet set (the lower girdles) has a great impact on diamond appearance and also alters the nature of the observance of scintillation in diamonds as well.

I''m really trying to understand the subject, but the amount of knowledge out there is very, very limited to the average Joe. It all seems so subjective that there almost isn''t a right or wrong answer. But if I read an AGS report and it tells me that the light performance is zero, how do they get that number is what I want to know.

Do a search on the ASET and you''ll understand how AGS arrives at their conclusion. If you have any further questions we''re here for ya.

Peace,

 

[Garry H (Cut Nut)]

all good stuff so far.

HCA scintillation is also attempting to describe "pattern" or negative contrast zones in a diamond - e.g. fisheye, nail head, ring or darkness from leakage etc.

AGS are still wrestling with scintillation. GIA got no further than I did and gave up too 9as admitted in the Foundation article).

a diamond is like a set of windows and mirrors. If you can see brighter parts of the environment- lights - thru the windows and mirrors then you can see a bright sparkle (and the stone scintilates).
Some stones like princess and radiants create more smaller sparkles - but these are often as a result of multiple internal reflections = less intense bright spots and if they are too weak or too small then our eye can not resolve them. Another reason why computers and fixed lighting models often fail.

Sergey has a solution, but we big need money for a large survey to calibarate his software to humans. Have a good look at this chart. It indicates the probability of a human with normal eyesight being able to see a sparkle in a diamond with x light sources. Note that as the exact same same facet structure gets larger the princess will look better than the round. if you can compare very big rounds to very big princess / radiants etc - you will find it is true.

For that reason sergey wants to radically change thinking and we hope to be offering software to guide for the optimum way to cut for any shape AND any size of stone.

 

[zhuzhu]

So, if I understood experts'' answers correctly, an emerald cut diamond will by nature have a lot less scintillation compared to a brilliant round because of the "step cut" faceting and larger table area?

How does different shape of diamond "measure up" in the best scintilation arena? Thanks!!

 

[Garry H (Cut Nut)]

Date: 4/6/2006 11:19:21 PM
Author: zhuzhu
So, if I understood experts'' answers correctly, an emerald cut diamond will by nature have a lot less scintillation compared to a brilliant round because of the ''step cut'' faceting and larger table area?

How does different shape of diamond ''measure up'' in the best scintilation arena? Thanks!!

Zhu if you study the image above you can see that a square stone will likely only gather light from certain directions. There fore there will be very little scintillation as the lights could well be in the wrong places and the stone can look quite dead compared to a nice round of larger princess cut.

 

[strmrdr]

Date: 4/7/2006 1:56:32 AM
Author: Garry H (Cut Nut)

Date: 4/6/2006 11:19:21 PM

Author: zhuzhu

So, if I understood experts'' answers correctly, an emerald cut diamond will by nature have a lot less scintillation compared to a brilliant round because of the ''step cut'' faceting and larger table area?


How does different shape of diamond ''measure up'' in the best scintilation arena? Thanks!!

Zhu if you study the image above you can see that a square stone will likely only gather light from certain directions. There fore there will be very little scintillation as the lights could well be in the wrong places and the stone can look quite dead compared to a nice round of larger princess cut.

unless its an asscher which do a better job than pretty much any cut at drawing light from any/all angles.

A well cut emerald cut will have a large broad flash when rotated along the longest axis.
An asscher will have a large broad flash when rotated any way.
This is in contrast to the smaller but more of them flashes of a RB or princess.
Totally different look and performance and both are kicken

 

[Garry H (Cut Nut)]

I like asschers 2 storm

 

[klavigne]

Hello Rhino and Dave,
All very interesting stuff to say the least. I think I''m starting to grasp this all now. So the realy easy answer to all of this is to stick with the FIC, TIC, and BIC parameters to find the "style" of flashes I''m after. So if I want lots of little pin flashes the FIC numbers would keep me happy, if I want lots of broad flashes the BIC numbers will keep me happy and if I want both the TIC numbers should keep me happy? I''ve heard that the FIC stones are getting more and more rare and lots of cutters aren''t doing them anymore because they aren''t as valuable, I think I heard that AGS/GIA penalizes them on the numbers?

 

[strmrdr]

Date: 4/7/2006 8:36:45 AM
Author: klavigne
Hello Rhino and Dave,

All very interesting stuff to say the least. I think I''m starting to grasp this all now. So the realy easy answer to all of this is to stick with the FIC, TIC, and BIC parameters to find the ''style'' of flashes I''m after. So if I want lots of little pin flashes the FIC numbers would keep me happy, if I want lots of broad flashes the BIC numbers will keep me happy and if I want both the TIC numbers should keep me happy? I''ve heard that the FIC stones are getting more and more rare and lots of cutters aren''t doing them anymore because they aren''t as valuable, I think I heard that AGS/GIA penalizes them on the numbers?

Its not that easy...
The lgf% plays a huge role in the pin fire / broad flash look in RB diamonds. More so in my opinion than the c/p angles until you get into the FIC range. Then the tall crown takes over more.

Remember that the pavilion and the LGF facets drive light return.
They are the reflectors that make diamonds work.
There is a very narrow range of good pavilion angles from about 40.3 to 41.3 with matching crown angles that rock but the range of crown angles that can be kicken when matched up with the proper pavilion angle ranges from 33 to 37 a lot wider range.
By keeping that in mind its plain that the pavilion is much more critical.
For example a 40.7P angle with work well with crowns from 33 to around 35.5 or so but a crown angle of 36 will works well with 40.3-40.5P angles.

 

[Rhino]

Interesting stuff Garry. I look forwarding to seeing these algorithyms incorporated into the DC software and how they corellate to observation. As I state in my tutorial on the subject, I don''t think scintillation is a fair characteristic to place a grade on since the varying appearances appeal to different personality types.

All the best,

 

[Rhino]

Date: 4/7/2006 8:36:45 AM
Author: klavigne
Hello Rhino and Dave,
All very interesting stuff to say the least. I think I''m starting to grasp this all now. So the realy easy answer to all of this is to stick with the FIC, TIC, and BIC parameters to find the ''style'' of flashes I''m after. So if I want lots of little pin flashes the FIC numbers would keep me happy, if I want lots of broad flashes the BIC numbers will keep me happy and if I want both the TIC numbers should keep me happy? I''ve heard that the FIC stones are getting more and more rare and lots of cutters aren''t doing them anymore because they aren''t as valuable, I think I heard that AGS/GIA penalizes them on the numbers?

Hi k,

I think you missed my comments above ... let me restate.

Okay John,
So what your talking about is the differences in a FIC, BIC & TIC stone. But I thought those were all based on crown/pav angles, along with table percentages.

Nope. Garry''s FIC, BIC and TIC are exactly as you describe ... based solely on table/crown/pavilion angles. Broad flash vs pin flash or a combo of the 2 requires a knowledge of lower girdle facet & star facet length and upper girdle angles. Since the HCA does not take these facet measurements into account, it is my professional opinion that the scintillation measurement on the HCA is not a good thing to use as an indicator to determine the nature or type of scintillation a person is looking for. I can show you 2 diamonds that have identical scintillation readings on the HCA (with similar crown/pavilion/table data) that vary dramatically in their scintillation and appearance. BIC, FIC and TIC have nothing to do with it.

Peace,

 

[oldminer]

I know not everyone agrees with what I am going to re-state here, but I believe the truth of it will come into acceptance over a relatively short time period. The light components of a diamond''s beauty can be measured by (3) three things: Light Return=Brilliance, Sparkle=Potential for scintillation, and Intensity=Contrast. These terms have been defined thoroughly before and I won''t put that here again. They are on my website for anyone who never saw the definitions.

The regular run of colorless to slightly tinted diamonds can be selected for beauty based on these three things. This covers the vast majority of diamonds being offered for sale. Fancy colored diamonds often make use of reduced light return in hopes of creating more apparent darkness and fooling the eye into seeing more depth of fancy color. It works, so a measure of light return might be compromised with fancy colors.

Fire: I classify this as a secondary characteristic and not the way to grade a diamond. You can only have so much fire before something unwelcome would happen to beauty. More is not always better. Tiffany & Co selects diamonds with very little fire. They have a world of experience and they know what they are doing. We can hardly question their choice. If anything, I''d use their knowledge and say it may be a proper way to go. It is their corporate taste and image, but no one can say they don''t know diamonds.

We have parameters of beauty which are universal for picking beautiful faces of people. Fire is something like skin color. We may agree on the universality of beautiful faces, but, in the end, we may select the face we think most beautiful based on personal preference, not on ultimate beauty.
Fire is very elusive and light dependent. We believe we can select the best diamonds without reference to a fire, colored light return, measured or estimated. I see nothing wrong with measuring it separately, but it does not need to be part of an overall grade of beauty. In fact, putting fire into the overall judgment of beauty may serve to needlessly restrict the wide range of super looking diamonds that might be cut.

Refracted light is what diamond light return is mostly about. Some degree of reflected light is also part of the mix. However, without refraction, no diamond would be a "winner". Good polish or better seems to play a very small role in overall satisfaction.

 

[strmrdr]

Dave since our past conversations Iv given it some thought.
Well cut diamonds that return mostly colored light and those that return mostly white light score about the same on total light output according to what you have said and fall within the same range in Brilliance as measured by imagem.
kewl I can agree there.

contrast is important - kewl there - where the contrast is located can make a huge difference however.



but none of the above will tell you the personality of a diamond and fire or colored light return is a very large part of a diamonds personality.
the question then becomes does - personality + performance == quality
If so then fire can not be discounted.

 

[Rhino]

Greetings Dave,

Just reading your comments here and would just like to ask a question on one.

Light Return=Brilliance

In devices like the Imagem and the BrillianceScope and lets throw reflectors into the mix as well since they show a critical analysis of which facets are functioning as reflectors/non-reflectors ...

If we take this base definition of Light Return = Brilliance, this is making a braod assumption that *any diamond* as long as it has high/veryhigh Imagem, BrillianceScope and reflector image will be a "very brilliant" diamond. Would this include all common lighting environments or limited lighting environments according to your thoughts/definition?

Peace,

 

[Garry H (Cut Nut)]

Guys the simplest analogy here is a chess board vs a sheet of white card.

The white card has 2X more light return, but zippo scintialltion and less brilliance than the chess board (which only returns 1/2 as much light).

 

[oldminer]

Rhino, Imagem uses one "normal" lighting model to discern total light return. Extensive and rigorous testing has shown that this lighting model gives results that human observers have agreed with. There is no question that different lighting can create unusual scenarios, but for grading diamonds we must have a repeatable, normalized lighting environment that generally gives results which human grading confirms as correct.

I would love to make certain that nail head types are automatically discarded regardless of the possibility one or two types of these might have high light return. With that goal in mind I have asked in several places for such stones, but have noit had much luck in the quest. I only need a couple for a day or two and will pay all costs involved. Anyone have a nailhead laying about???

 

[Rhino]

Date: 4/7/2006 8:01:29 PM
Author: Garry H (Cut Nut)
Guys the simplest analogy here is a chess board vs a sheet of white card.

The white card has 2X more light return, but zippo scintialltion and less brilliance than the chess board (which only returns 1/2 as much light).

No fair Garry ... you know my thinking on this.

 

[Rhino]

Hi Dave,

I guess a good question to ask would be ... what lighting environment is it doing its analysis in? My educated guess would be direct lighting and not diffuse. Correct me if I''m wrong.

Kind regards,

 

[Rhino]

Ooops... forgot to mention. No nailheads in the inventory.

If you like you can perform a search on our site (must click "advanced search") and check off the "optical symmetry" option. This way you can search with this criteria. Search among stones with "common" optical symmetry and if you see any stones there you''d like to test on the Imagem I''ll be more than happy to send them to ya bro.

Peace,

 

[squarediamondlove]

Garry, Can you elaborate a bit on this model, specifically what the pin points represent.

From what I understood, your point is that larger diamonds of the same shape perform differently than the smaller one - so that a 2mm princess will underperform a round substantially, but a 12 mm princess will do better than a 12 mm round?
Am I getting this right? If that is so, the larger princess will do better in exactly what? Scintillation? can you explain more why that is and what contributes to that? Thanks!

 

[Garry H (Cut Nut)]

Date: 4/8/2006 2:50:48 AM
Author: Kaleidoscopic
Garry, Can you elaborate a bit on this model, specifically what the pin points represent.


From what I understood, your point is that larger diamonds of the same shape perform differently than the smaller one - so that a 2mm princess will underperform a round substantially, but a 12 mm princess will do better than a 12 mm round?

Am I getting this right? If that is so, the larger princess will do better in exactly what? Scintillation? can you explain more why that is and what contributes to that? Thanks!

correct K, it shows the likelyhood of being able to see a light thru a virtual ''windows and mirrors set'' in a part of the diamond.

The name of this concept is ETAS - Effective Total Angular Size - but the name is not very helpful.

The great benefit of ETAS is that it can handle all the variables - eg the size of the light, the nature of the beams or rays emmitted from it. The aperature of your pupil (bigger in dark = you see more fire / broader part of the spectrum) and it allows for two eyes - stereo vision etc.

Dynamic ETAS can show the sparkles you would see as the stone moves. But here in lies one example of why ETAS needs calibration.

Imagine you are hunting / hunted by a big tiger. you see the tiger bounding thru a thick forest in your general direction and raise your bow and arrow in readiness. You catch glimpses of the tiger, which you are able to mentally join into a pattern of the direction in which to release your arrow. You actually never see the entire tiger - you see bits of her in dynamic movement for about 3% of the area you are looking.

And whap!

Your arrow hits your target and the tiger crashes to the ground.

Your ability to do this amazing feat was inhereted genetically. Those who did not inherit that ability were tiger food generations ago.

We diamond lovers have that inherent ability and it allows us to "see" move sparkles than are actually there.

Sergey''s software can measure the ''potential'' for our ability to make 3% of ''seen'' scintialltion into a far bigger imagined perception. But he needs to run calibration testing - and that can only be done with a global human observation testing with stones cut to precise and exacting standards and with specific controlled lighting etc.

We know what needs to be done - but we do not have any benefactors who will put up a few million dollars to make it happen. (Actually there is one diamantaire who would like to fund it - but Sergey would not accept funds from a single commercial source - we probably need a minimum of 3 for the perception of imdependance.

I am not at my computer - so can not give you any more samples - but if you and others are interested then keep this thread alive and I will share stuff when I get home tonight.