Discussion of green in an ASET image

[ChunkyCushionLover]

43.9 takes a large hit in yield which is why most are cut in the 50% area.

Can you explain how you know it takes a hit in yield? Intuitively If inside stone(spotted outline) were cut with steeper pavilion angles more rough would be retained. (Assume black outline is rough not already faceted). Top example.

But the opposite would also be true if the rough were more shallow (bottom example) wouldn't it?

The diamond will be cut as dictated by the rough.
If the rough is shallow then the stone will be cut shallower.
If the rough will allow it and it does much of the time a deeper pavilion would be cut to keep the weight.

Yeah thats all fine and pretty intuitive, but what shape of rough is chosen for marquise usually?
Have pictures or diagrams?

 

[Karl_K]

ccl,

usually macles

 

[ChunkyCushionLover]

ccl,

usually macles

The power of google I see that diagram when I google marquise plus rough.
But I am perhaps too experienced to see how that rough can be efficiently cut in stones with (50 + 14 + culet) 68% depth like the design we are discussing here.

Thanks for your time in this thread Karl genuinely appreciated.

 

[ChunkyCushionLover]

ccl,

usually macles

The power of google I see that diagram when I google marquise plus rough.
But I am perhaps too experienced to see how that rough can be efficiently cut in stones with (50 + 14 + culet) 68% depth like the design we are discussing here.

Thanks for your time in this thread Karl genuinely appreciated.

Inexperienced not experienced.

 

[Garry H (Cut Nut)]

A marquise would usually be a secondary or tertiary stone - but you are off topic guys

 

[Garry H (Cut Nut)]

for example
http://www.youtube.com/watch?v=yiOcI20GD2s

 

[ChunkyCushionLover]

That is a concept I can visualize and understand, helium polish is a wonderful program.
The OP has left the building and posted another thread ignoring this one.

 

[Rockdiamond]

Karl is correct CCL.

I hope this helps - a model of a yellow diamond, and you can see here that I have shot a ray thru the ciercled area which is one of the stronger yello zones because the ray path (set to 40 bounces) is huge - probably averaging 15 times diameter.

I counted all the exit rays and 70% or the light is leaving via the pavilion - 30% above (not counting the 17% reflection).

Hi Garry,
I restarted the computer- diacalc is in my program files, but fails to open when I click on it- I've tried a bunch of times.
I have windows 7, if that matters.....

I did start a new thread- more general in nature.
Please allow me to paraphrase and let me know if I get the drift of your quoted post.
A light ray entering that point on the diamond bounces 40 times, the combined length of the path the light travels is 15 times the diameter of the stone.
After that 70% of the light is directed down through the pavilion as it finally exits the diamond.

If that's correct: you mentioned "set to 40 bounces"- does that mean you asked the simulation to bounce the light that many times?
If so, how dies this relate to real life?
Further, how does it relate to seeing yellow on the aset?

 

[diagem]

That is a concept I can visualize and understand, helium polish is a wonderful program.
The OP has left the building and posted another thread ignoring this one.

Shape of the rough is just one factor out of many when deciding which polished shape and facet design to cut.

DC is a great simulator for understanding a theoretical aspect of the cutting procedure, its a perfect world vs. a heavily complicated world on the real material.

 

[Garry H (Cut Nut)]

RD had every right to start a new thread when you guys took this one meandering.

Karl is correct CCL.

I hope this helps - a model of a yellow diamond, and you can see here that I have shot a ray thru the ciercled area which is one of the stronger yello zones because the ray path (set to 40 bounces) is huge - probably averaging 15 times diameter.

I counted all the exit rays and 70% or the light is leaving via the pavilion - 30% above (not counting the 17% reflection).

Hi Garry,
I restarted the computer- diacalc is in my program files, but fails to open when I click on it- I've tried a bunch of times.
I have windows 7, if that matters.....



I did start a new thread- more general in nature.
Please allow me to paraphrase and let me know if I get the drift of your quoted post.
A light ray entering that point on the diamond bounces 40 times, the combined length of the path the light travels is 15 times the diameter of the stone.
After that 70% of the light is directed down through the pavilion as it finally exits the diamond.

If that's correct: you mentioned "set to 40 bounces"- does that mean you asked the simulation to bounce the light that many times?
If so, how dies this relate to real life?
Further, how does it relate to seeing yellow on the aset?

In real life David the light bounces as many times as it does until it has all exicted (or been consumed by lack of transparency).
In colored diamond planning we measure the average # of bounces by raypath length divided by diameter - it can under 4 for a well proportioned round and closer to 10 for a perfect crushed ice stone.
The blue in ASET would be almost always straight in and straight out - so can be around 1.5x - which means you only see the whole facet and not any splitting up for virtual facets.

The yellow is because I used a yellow diamond model - the yellow would be white if it was a white diamond.

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes crushed ice, and also to show that in the green areas the leakage zones are usually very small and can add contrast - but they especially work well for color - because as you can see - the leakage areas are often stronger yellow - indicating a longer ray path - and even if the light escapes out the pavilion - the color is still enhanced.

Sorry for ramble - read 2 -3 times please

 

[ChunkyCushionLover]

That is a concept I can visualize and understand, helium polish is a wonderful program.
The OP has left the building and posted another thread ignoring this one.

Shape of the rough is just one factor out of many when deciding which polished shape and facet design to cut.

DC is a great simulator for understanding a theoretical aspect of the cutting procedure, its a perfect world vs. a heavily complicated world on the real material.

You mean Helium Rough not DC right?
http://www.octonus.com/oct/products/helium/rough/
Do you use it?

 

[ChunkyCushionLover]

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes
the green areas the leakage zones are usually very small and can add contrast.

Usually very small areas of leakage? I disagree, RD's radiant happened to be a more square ORC with steeper angles and shorter ray paths than your typical ORC and certainly better than the average generic radiant. The size of the leakage areas are often equal in size to the size of the active VFs.

 

[Garry H (Cut Nut)]

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes
the green areas the leakage zones are usually very small and can add contrast.

Usually very small areas of leakage? I disagree, RD's radiant happened to be a more square ORC with steeper angles and shorter ray paths than your typical ORC and certainly better than the average generic radiant. The size of the leakage areas are often equal in size to the size of the active VFs.

In good crushed ice CCL there is always very small virtual facets with a good distribution of lower angle multiple internal reflections.

Do you know what causes the leakage we often see in the center of princess cuts - it is not direct leakage out the pavilion because the facet angles are way deeper than 24.5 degrees (critical angle).

 

[ChunkyCushionLover]

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes
the green areas the leakage zones are usually very small and can add contrast.

Usually very small areas of leakage? I disagree, RD's radiant happened to be a more square ORC with steeper angles and shorter ray paths than your typical ORC and certainly better than the average generic radiant. The size of the leakage areas are often equal in size to the size of the active VFs.

In good crushed ice CCL there is always very small virtual facets with a good distribution of lower angle multiple internal reflections.

Do you know what causes the leakage we often see in the center of princess cuts - it is not direct leakage out the pavilion because the facet angles are way deeper than 24.5 degrees (critical angle).

Garry please define "good crushed ice" I don't want to misinterpret again.
As for princess provide .gem with leakage in the centre (ASET white not green) so I know what you are referring to.

If you are talking about ASET green X in center I have a pretty good idea why that is, too shallow pavilion angles and shallow crown makes the X larger. High angle light bounces off opposite side pavilion then exits crown at a low angle away from viewer's eye. Reverse the lightpath and have the source at low angle and you get light back to the viewer's eye.



Do you know how to control the angle of the incoming rays in DC ray trace to hit a more specific area of the crown originating from a particular incident angle?, if I knew how to do that it would be much easier to show these things. Doing it backwards and having to tilt the stone in profile is cumbersome.

 

[ChunkyCushionLover]

Leaky White X even shallower pavilion angle.
Pavilion mains at 39 degrees.
I forgot to turn dispersion off centre in ASET should be blue not white, it gets a blue tinge from dispersion.

 

[Rockdiamond]

RD had every right to start a new thread when you guys took this one meandering.

Karl is correct CCL.

I hope this helps - a model of a yellow diamond, and you can see here that I have shot a ray thru the ciercled area which is one of the stronger yello zones because the ray path (set to 40 bounces) is huge - probably averaging 15 times diameter.

I counted all the exit rays and 70% or the light is leaving via the pavilion - 30% above (not counting the 17% reflection).

Hi Garry,
I restarted the computer- diacalc is in my program files, but fails to open when I click on it- I've tried a bunch of times.
I have windows 7, if that matters.....



I did start a new thread- more general in nature.
Please allow me to paraphrase and let me know if I get the drift of your quoted post.
A light ray entering that point on the diamond bounces 40 times, the combined length of the path the light travels is 15 times the diameter of the stone.
After that 70% of the light is directed down through the pavilion as it finally exits the diamond.

If that's correct: you mentioned "set to 40 bounces"- does that mean you asked the simulation to bounce the light that many times?
If so, how dies this relate to real life?
Further, how does it relate to seeing yellow on the aset?

In real life David the light bounces as many times as it does until it has all exicted (or been consumed by lack of transparency).
In colored diamond planning we measure the average # of bounces by raypath length divided by diameter - it can under 4 for a well proportioned round and closer to 10 for a perfect crushed ice stone.
The blue in ASET would be almost always straight in and straight out - so can be around 1.5x - which means you only see the whole facet and not any splitting up for virtual facets.

The yellow is because I used a yellow diamond model - the yellow would be white if it was a white diamond.

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes crushed ice, and also to show that in the green areas the leakage zones are usually very small and can add contrast - but they especially work well for color - because as you can see - the leakage areas are often stronger yellow - indicating a longer ray path - and even if the light escapes out the pavilion - the color is still enhanced.

Sorry for ramble - read 2 -3 times please

Great explanation Garry- thank you for that.

CCl- you've asked Garry to define "good crushed ice"- I suggest that instead of "good" we find more descriptive, less judgmental terms to describe this phenomenon- and it's variations.

 

[ChunkyCushionLover]

I still prefer these definitions from Rhino (I modified them to remove the subjective comments) :

Regarding "crushed ice" look of diamond there are currently two ideas that come to mind when people say this in the realm of diamonds.

It can refer to

a. A really bright diamond whose optical characteristics emphasize many small flashes of of white light in diffuse/ambient lighting and a ton of scintillation in spot lighting.
b. A diamond that exhibits less light return and at best reflects back small pinpoints of light. The "crushed ice" effect here could be more accurately described as "dark, sometimes watery, slushy crushed ice".

In scenario a. above the facet design and size of physical facets is highly responsible for the small bright reflections and high scintillation.

In scenario b. above facet design has little to do with the watery crushed ice effect as you can get it in many facet designs.
What contributes to it primarily is proportion factors and you can have it in both chunky/vintage faceted diamonds as well as modern or modified brilliant facet designs. Most radiants and many cushions are cut in this fashion as well and is generally the result of pavilion angles that are cut too shallow coupled with crown angles that contribute to the excessive leakage existing under the table.

 

[Rockdiamond]

First, let me thank you ccl- as it seems clear you're interested in a new tone in our discourse.

If you read your own answer you may realize part of what I see as subjective impressions- as opposed to objective ones.
For example "less light return and at best reflects back small pinpoints of light"
This might very well be an accurate description in one lighting scenario, but maybe not in all.
Then, we have the thorny issue of classifying light return. How do we know one stone exhibits more light return?
I suppose the aset is supposed to do that- and very well may, in it's own way. But if we change a few variables, the amount of light coming back- relative to a comparison stone- will change.

Then we have the "dark watery slushy crushed ice" descriptive.
Again, I honestly feel we're adding subjective comments into an objective discussion. If a stone has dark zones, that is a more objective manner of describing what we see.

"Most radiants and many cushions are cut in this fashion as well and is generally the result of pavilion angles that are cut too shallow coupled with crown angles that contribute to the excessive leakage existing under the table."

Lastly- I think that assumptions including phrases such as "most cushions are cut this way or that way" may lead to incorrect conclusions. I see so many different looks in both radiant and cushions I personally would not generalize.

There are only suggestions that might allow a more objective dialog.

 

[Garry H (Cut Nut)]

Attempt at definition

Good crushed ice diamonds appear to have an overal very even array of very small flashes that 'roll' as the stone is rocked from side to side. There should be no easily identified larger dark zones (which can be most commonly the result of head obstruction, or leakage). All the flashes should be very small resuting in a pinfire effect.
The cause of the appearance of an exceptionally large number of facets is the many internal reflections which split the observed facet structure at each internal reflection.
The contrast between bright and dark areas is often contributed to positively by very small zones of leakage, where-as in well cut rounds the main cause of (larger) contrasting dark zones is obstruction as per the way the star effect often appears dark and with a slight movement the dark quickly flashes to a very intense bright zone.
A good crushed ice diamond will apear to have much less brightness than a good round, but the overall uniform brightness can make these stones appealing.
I have rarely seen good colorless crushed ice diamonds, but frequently see good examples in colored diamonds where there is a much larger premium for the skill and expertise involved in producing the color adding benefits resulting from the longer ray paths.

So in some crushed ice diamonds it might be possible for the human eye to vaguely see some light after 40 bounces - but probably only a very bright source like the sun and then it might be a grey facet rather than a black one. It was an excercise to show what causes
the green areas the leakage zones are usually very small and can add contrast.

Usually very small areas of leakage? I disagree, RD's radiant happened to be a more square ORC with steeper angles and shorter ray paths than your typical ORC and certainly better than the average generic radiant. The size of the leakage areas are often equal in size to the size of the active VFs.

In good crushed ice CCL there is always very small virtual facets with a good distribution of lower angle multiple internal reflections.

Do you know what causes the leakage we often see in the center of princess cuts - it is not direct leakage out the pavilion because the facet angles are way deeper than 24.5 degrees (critical angle).

Garry please define "good crushed ice" I don't want to misinterpret again.
As for princess provide .gem with leakage in the centre (ASET white not green) so I know what you are referring to.

If you are talking about ASET green X in center I have a pretty good idea why that is, too shallow pavilion angles and shallow crown makes the X larger. High angle light bounces off opposite side pavilion then exits crown at a low angle away from viewer's eye. Reverse the lightpath and have the source at low angle and you get light back to the viewer's eye.



Do you know how to control the angle of the incoming rays in DC ray trace to hit a more specific area of the crown originating from a particular incident angle?, if I knew how to do that it would be much easier to show these things. Doing it backwards and having to tilt the stone in profile is cumbersome. split the view and you can move the ray in either window so you have the usual E-W as well as N-S control - does that help?

The default 3 chevron princess has the clear leakage central zone CCL.

 

[Rockdiamond]

Attempt at definition

Good crushed ice diamonds appear to have an overal very even array of very small flashes that 'roll' as the stone is rocked from side to side. There should be no easily identified larger dark zones (which can be most commonly the result of head obstruction, or leakage). All the flashes should be very small resuting in a pinfire effect.
The cause of the appearance of an exceptionally large number of facets is the many internal reflections which split the observed facet structure at each internal reflection.
The contrast between bright and dark areas is often contributed to positively by very small zones of leakage, where-as in well cut rounds the main cause of (larger) contrasting dark zones is obstruction as per the way the star effect often appears dark and with a slight movement the dark quickly flashes to a very intense bright zone.
A good crushed ice diamond will apear to have much less brightness than a good round, but the overall uniform brightness can make these stones appealing.
I have rarely seen good colorless crushed ice diamonds, but frequently see good examples in colored diamonds where there is a much larger premium for the skill and expertise involved in producing the color adding benefits resulting from the longer ray paths.

A very precise definition Garry- extremely well put.
The only thing I would change is the word "good"
Instead of what you've described so well as being "good Crushed Ice", how about "Non Patterned, Even Crushed Ice"

I also agree nice examples are rare- but no more so than really great patterned stones in fancy shapes.
Really well cut stones - by the measures generally accepted by the trade are rare in Fancy Shapes.

I can also make a case for the appeal of stones that exhibit crushed ice- yet also show some patterning.

 

[ChunkyCushionLover]

Attempt at definition

Well cut crushed ice diamonds appear to have an array of small flashes that cover the diamond from edge to edge as the stone is tilted.

No patterning means the array cannot be even or symmetrical.

Contains few dark zones (caused by obstruction or persistant leakage). All the flashes should be small resuting in a pinfire effect.

Darker zones is not defined and by definition a leakage zone in a static image would be darker than the active VFs at that snapshot.

The cause of the appearance of an exceptionally large number of facets is the many internal reflections which split up the physical facet structure at each internal reflection.

The contrast between bright and dark areas is often contributed to positively by very small zones of leakage, where-as in well cut
rounds the main cause of (larger) contrasting dark zones is obstruction as per the way the star effect often appears dark and with a slight movement the dark quickly flashes to a very intense bright zone.

I prefer

They have faster scintillation(sparkle) caused by smaller virtual facets that were created by small leakage zones. This is in contrast to well cut rounds which have larger virtual facets and slower scintillation, which is caused by obstruction of the pavilion mains which forms a star pattern that can be the source of great brightness and fire upon movement.

A good crushed ice diamond will apear to have much less brightness than a good round, but the overall fast scintillation can make these stones appealing in some lighting.

By definition they don't have uniform brightness. The fast scintillation can make the stones appealing especially under strong directional lighting.

I have rarely seen good colorless crushed ice diamonds, but frequently see good examples in colored diamonds where there is a much larger premium for the skill and expertise involved in producing the color adding benefits resulting from the longer ray paths.

Tons of colored diamonds have crushed ice especially fancy yellow radiants, they lack the brilliance of colorless diamonds but make up for it in uniformity and saturation of color. You see a premium for proper crushed ice design(ie better cut fancy yellow radiants)?

I instead see a premium for highly saturated material which can be cut with more brilliance as the cutter doesn't have to worry about washing out the color.

The default 3 chevron princess has the clear leakage central zone CCL.

Yeah I see, same thing as my second example 39 degree pavilion main angle.

 

[Garry H (Cut Nut)]

Attempt at definition

Good crushed ice diamonds appear to have an overal very even array of very small flashes that 'roll' as the stone is rocked from side to side. There should be no easily identified larger dark zones (which can be most commonly the result of head obstruction, or leakage). All the flashes should be very small resuting in a pinfire effect.
The cause of the appearance of an exceptionally large number of facets is the many internal reflections which split the observed facet structure at each internal reflection.
The contrast between bright and dark areas is often contributed to positively by very small zones of leakage, where-as in well cut rounds the main cause of (larger) contrasting dark zones is obstruction as per the way the star effect often appears dark and with a slight movement the dark quickly flashes to a very intense bright zone.
A good crushed ice diamond will apear to have much less brightness than a good round, but the overall uniform brightness can make these stones appealing.
I have rarely seen good colorless crushed ice diamonds, but frequently see good examples in colored diamonds where there is a much larger premium for the skill and expertise involved in producing the color adding benefits resulting from the longer ray paths.

A very precise definition Garry- extremely well put.
The only thing I would change is the word "good"
Instead of what you've described so well as being "good Crushed Ice", how about "Non Patterned, Even Crushed Ice"

I also agree nice examples are rare- but no more so than really great patterned stones in fancy shapes.
Really well cut stones - by the measures generally accepted by the trade are rare in Fancy Shapes.

I can also make a case for the appeal of stones that exhibit crushed ice- yet also show some patterning.

David in my opinion a crushed ice stone is evenly crushed ice with no other chunky facets or paterns. So calling it Non patterned or even is actually covered in my definition (yes? no?)
If it has that then it is some other variant. For example, an xyz cut with 4 large main facets and the rest of the stone is crushed ice.
As to appeal - a definition is not a grade. And i deliberately used "good" and not a superlative.

 

[Rockdiamond]

I see your point Garry- but how do we categorize the "xyz" stone?

 

[Garry H (Cut Nut)]

I see your point Garry- but how do we categorize the "xyz" stone?

Take a typical marquise - lets use your stone on the first post on this page.
It has 3 main zones in the images you posted.

1. lots of crushed ice from tip to near the mid zones described next.

2. a central dark bow tie which is the same as a nail head (GIA confused a lot of the people who taught you decades ago because they taught this darkness was caused by leakage. It is not - it is the nail head that yoou see when you look at the head of a shiny nail - ie you see yourself, and even as you tilt the daimond this effect seems to stay for ages. Again I asked you to look thru a sheet of paper with a small 1/4 inch hole and you will see all nailheads and bowties willl disappear - you say it does not - I have had many hundreds of gemo's and appraisers in diamond classes, and so far you are the only one who never saw it. Most disagreed until they did it for themselves.)
Note in your second photo the dark zone is larger and encroaches on some of the red zone in the ASET. It is because you have the camera closer than in the other shot and you are blocking around 40 degrees of the 180 above the stone.

3. the bright zones - mainly where the red is - are just like any round diamond. They are typically in the cross section where the proportions are a bit like a well cut round.

 

[Rockdiamond]

When I said xyz strone- I was thinking of radiant or cushion.

Are you saying dark zones at the edges- or not in the center- of radiant cuts, or cushion modified stones share the same cause?

I did try the experiment- but for me the problem was I could not focus one eye through the small hole. Not saying it's not interesting, but what is the real life relevance of the cause?

 

[Garry H (Cut Nut)]

When I said xyz strone- I was thinking of radiant or cushion.

Are you saying dark zones at the edges- or not in the center- of radiant cuts, or cushion modified stones share the same cause?
yes
I did try the experiment- but for me the problem was I could not focus one eye through the small hole. Not saying it's not interesting, but what is the real life relevance of the cause?

to get the idea that there are red zones that are border line blue's etc

 

[Rockdiamond]

Reds can border blues or greens- that makes sense based on the physics.
I did see how moving the stone in and out had some green changing to red
We can see that a lot of really nice crushed ice stones are drawing light from lower angles.


I did an experiment with a few crushed ice radiant cuts and a GIA EX cut grade that scores a 1.9 on the hca.
I had an "ah-ha" moment regarding brilliance measurements.

By cupping my hand over the diamonds, it was clear that if you eliminate as much light as possible, a round cuts inherent advantage is clear- sorry for the bad focus, but I could see alot more white light coming back from the round there was very light getting in- but what was most going through the table


By uncupping my hand- just a little bit- that difference is hardly perceptible- in fact it's easy to make the case the crushed ice stones are brighter in this type of lower light


My point is that if a stone is gathering a lot of light from lower on the horizon sources, there will be times that may give it an advantage over the brighter round brilliant design.

 

[Garry H (Cut Nut)]

Reds can border blues or greens- that makes sense based on the physics.
I did see how moving the stone in and out had some green changing to red
We can see that a lot of really nice crushed ice stones are drawing light from lower angles.


I did an experiment with a few crushed ice radiant cuts and a GIA EX cut grade that scores a 1.9 on the hca.
I had an "ah-ha" moment regarding brilliance measurements.

By cupping my hand over the diamonds, it was clear that if you eliminate as much light as possible, a round cuts inherent advantage is clear- sorry for the bad focus, but I could see alot more white light coming back from the round there was very light getting in- but what was most going through the table


By uncupping my hand- just a little bit- that difference is hardly perceptible- in fact it's easy to make the case the crushed ice stones are brighter in this type of lower light


My point is that if a stone is gathering a lot of light from lower on the horizon sources, there will be times that may give it an advantage over the brighter round brilliant design.

So you see why I say that the more green and less blue the better
That way the observer ceases to be a source of dark zones = more even crushed ice.
So now you can flick through parcels and find the best fancy colors and crushed ice, or nice variants of the xyz type with pleasing patterns.
(BTW some people love the ORC oval / circular patterning - its a choice issue - just that for me crushed ice should be even and all crushed.)

 

[ChunkyCushionLover]

I think that in modern day research one must not make the mistake diamantaires have been making for years.
One should not flood a diamond with directional light like a lamp while making cut comparisons.

The pictures above are a perfect example of why, too much light obscures the difference that will be seen in normal viewing environments.

Pavilion lighting does the same thing.

With regards to cupping your hand or blocking light it depends on which angular range of light was blocked.

 

[BAM54321]

I hope you will paraphrase all four points properly and indicate your understanding in a reply before we move on so that I know you are reading and interpreting properly what I am trying to teach you. This can be the start for common ground and understanding.

Sorry, CCL, I understand in this new forum, the focus will best be content...but....despite what may well be your superior understanding, the size of the chip on your shoulder makes the content difficult to make out. That participation in a thread begun by another is optional is a further confound.

Just my 2 cents.

Ira Z.

Ira, thank you very much.
I resisted from responding in hopes cooler heads would prevail.
ccl- you clearly have a desire to learn, and to share that knowledge.
I have expanded my horizons by taking note of specific in facet design- and some of what you've written helped that.
On the other hand, please do not discount the value of real practical experience. For example, although I now refer to "8main Cushions", for me the distinction is one of words- I have been able to recognize the differences for many years, but now I have more ways to describe them.

Also, please keep in mind that subjective judgement will never be removed from any discussion of beauty in diamonds - or even quality of cut.

In terms of diacalc, and other simulations- I request that we limit this discussion to aset and it's relation to actual diamonds- I will be happy to procure stones specifically for this purpose.
The reason behind this request is to prevent the discussion from getting overly technical- this way more people may get benefit from it.[/quote]

I appreciate the 'experts' (trade and otherwise) sharing their knowledge, and realize that alot of the conversation will be technical in nature, but agree with David that it is best (whenever possible) to limit the discussion to the specific topic at hand. I try hard to follow along, but sometimes get overwhelmed when someone uses 'ten topics' to expain 'one topic.' Although all of the information intertwines, and there is often a need to delve into one thing to explain another, it would be helpful if those in the know tried to stay on point as much as possible. A conversation about math that starts with adding and then jumps to advanced calculus will lose alot of eager math students.