Is leakage bad?

[Laila619]

Okay. I'm a very patient and fair person and always give people the benefit of the doubt. But even I am starting to get suspicious about these sorts of threads and the motives behind them.

I'm not sure I understand the point of endlessly rehashing steep deeps, leakage, and obstruction. YES, in general they are bad, and NO, in general no one who knows about diamonds would want to own such stones.

I agree, Rockdiamond, that one should never stop asking questions and trying to learn new things. Instead of debating about the merits of leakage and obstruction, why not start a more useful debate, like FICs vs TICs vs BICs or something like that.

 

[Michael_E]

Date: 12/7/2009 8:09:39 PM
Author: princesss
Basically, if I look at a stone and think, ''I could drive a truck through that window!'' it''s leakage. If it''s dark, but I can''t see the finger under the stone, it''s obstruction.

Unfortunately this is only correct for colored stones and not diamonds. Unless a diamond is an absolute train wreck of cutting, then you will never see a window through it or be able to see your finger, (even if it leaks like a sieve). One thing that has gone missing in this discussion is that darkness from "leakage" occurs in different areas of a round brilliant diamond than darkness from "obstruction". In even moderately cut diamonds which have significant leakage, it we be mostly evident around the perimeter of the stone and not under the table. Any darkness under the table will nearly always be caused by "obstruction" due to the cut being too deep. IN shallow stones any darkness under the table comes from increasing reflections coming from low on the horizon. I think that one of you guy''s with some "leaky" diamonds ought to toss up some pictures and label the leakage areas so that the meaning and location of this effect becomes more clear for everyone who isn''t clear about it.

 

[Kelli]

I apologize for commenting in this thread and not having read all of it, but I refuse to read two pages of a thread that seems exactly the same as several I''ve already gone through. In my diamond, YES!!! The leakage was bad. Very, very bad. that''s why I had it recut to better proportions, and now there''s no black hole in the middle of it. As much as I don''t like reading this conversation over and over, I wanted to add my opinion for anyone who hasn''t bought a diamond yet. I highly recommend getting the numbers and avoiding a "leaky" round brilliant diamond.

 

[ChunkyCushionLover]

Date: 12/7/2009 8:45:53 PM
Author: Laila619
Okay. I'm a very patient and fair person and always give people the benefit of the doubt. But even I am starting to get suspicious about these sorts of threads and the motives behind them.

I'm not sure I understand the point of endlessly rehashing steep deeps, leakage, and obstruction. YES, in general they are bad, and NO, in general no one who knows about diamonds would want to own such stones.

I agree, Rockdiamond, that one should never stop asking questions and trying to learn new things. Instead of debating about the merits of leakage and obstruction, why not start a more useful debate, like FICs vs TICs vs BICs or something like that.

What has he learned from this thread or any the others? Can he actually paraphrase anything that anyonelse has said to him or any correction to his muddled unscientific rambling generelizations about diamonds?
Does he ever paraphrase or demonstrate any knowledge gained from Pricescope?

Do any of you really think he really intends on listening to the answers?

I know what he has learned

that backlinks from Pricescope threads help his sites google search rankings and that confusing customers draws attention to his "niche" diamonds. But then again he knew these things before starting this thread.

 

[kenny]

Date: 12/8/2009 1:16:41 AM
Author: ChunkyCushionLover
... I know what he has learned

that backlinks from Pricescope threads help his sites google search rankings ...

David's company's name is in the sigline of every one of his posts.

So are you saying that every time he posts he comes up higher in Google searches when customers search for diamond vendors?

Wow.

No wonder he keeps conversations going on for ever and ever by asking the same question over and over and acting confused.
Smart man - and as long as he is polite and follows PS rules he can exploit PS for his gain forever with impunity.

It kind of makes me feel like a sucker for even talking to him.

CCL, I'm sure glad that you didn't boycott this thread.
You have let some sunlight in and now we see what's really going on - and actually this explains the repetition problem.
Boycotting would just let it continue unexposed and unchallenged.

 

[princesss]

Date: 12/7/2009 10:37:29 PM
Author: Michael_E

Date: 12/7/2009 8:09:39 PM
Author: princesss
Basically, if I look at a stone and think, ''I could drive a truck through that window!'' it''s leakage. If it''s dark, but I can''t see the finger under the stone, it''s obstruction.

Unfortunately this is only correct for colored stones and not diamonds. Unless a diamond is an absolute train wreck of cutting, then you will never see a window through it or be able to see your finger, (even if it leaks like a sieve). One thing that has gone missing in this discussion is that darkness from ''leakage'' occurs in different areas of a round brilliant diamond than darkness from ''obstruction''. In even moderately cut diamonds which have significant leakage, it we be mostly evident around the perimeter of the stone and not under the table. Any darkness under the table will nearly always be caused by ''obstruction'' due to the cut being too deep. IN shallow stones any darkness under the table comes from increasing reflections coming from low on the horizon. I think that one of you guy''s with some ''leaky'' diamonds ought to toss up some pictures and label the leakage areas so that the meaning and location of this effect becomes more clear for everyone who isn''t clear about it.

And just when I thought I had it! Shucks.

So if leakage is around the perimeter, is it caused by the facets being cut so that they don''t reflect the light back at the viewer? For instance, if light entered through the table, it bounced around off of the main facets and then "leaked" out around the edges instead of being reflected back to the viewer''s eye? Would that mean that the facets at the bottom (not sure what the proper term for those facets is) are misaligned or the facets near the edge?

The way I understand it, facets act as mirrors for light, and reflect the light back at the same angle they come in (not directly back out, but if it hits one side at an angle, it bounces off at the same angle on the other side, like when you hit a pool ball against the side of the table), which is why you need to line up the facets so precisely to get optimum light return. Is this correct? So if that is true, which poorly-aligned facets would result in leakage and which would result in obstruction? Or is it not that simple?

(And I guess an open culet is different than a window? Because I thought the Daussi cushion had an area in the middle where I could see the band through the stone. I''m a fan of open culets in OECs and OMCs, but are they the same things we''d consider "windows" in coloured stones?)

 

[Michael_E]

Date: 12/8/2009 9:38:36 AM
Author: princesss
So if leakage is around the perimeter, is it caused by the facets being cut so that they don't reflect the light back at the viewer? For instance, if light entered through the table, it bounced around off of the main facets and then 'leaked' out around the edges instead of being reflected back to the viewer's eye? Would that mean that the facets at the bottom (not sure what the proper term for those facets is) are misaligned or the facets near the edge?

The way I understand it, facets act as mirrors for light, and reflect the light back at the same angle they come in (not directly back out, but if it hits one side at an angle, it bounces off at the same angle on the other side, like when you hit a pool ball against the side of the table), which is why you need to line up the facets so precisely to get optimum light return. Is this correct? So if that is true, which poorly-aligned facets would result in leakage and which would result in obstruction? Or is it not that simple?

Alignment is important, but more important is the interaction of the angles of the crown and pavilion. The crown acts like a set of prisms on top of the pavilions mirrors. The leakage that you see in many of the diamond viewers, (ASET, etc.), is not really where you see it, but on the opposite side of the diamond. What you are seeing is a reflection of that leakage, kind of like looking through a periscope, where the light bounces a few times before it leaves the stone and enters your eye.

Obstruction is more straightforward and is most pronounced when looking through the table. This is because the table is flat and any light entering it is influenced mostly by the angles on the pavilion. Looking closely at any round diamond and you'll notice a brighter round octagon surrounded by the darker area of obstruction. That bright octagon is a reflection of light entering the table from around the sides of the obstruction, (your head). This works because the light entering at a lower angle through the table gets bent as it enters the stone to an angle which allows it to bounce around and exit directly into your eyes. As the pavilion angles, and depth, get larger that bright area gets smaller until it disappears and the entire center looks dark. This, of course, depends on how close your are to the stone, since as you move away from it the obstruction gets smaller. At some point you will be far enough away so that there is no effect from obstruction. Obstruction is also affected by crown angles and table sizes since the angled surfaces on the crown obtain light from areas to the side of the obstruction and so smaller tables can reduce overall darkness from obstruction, (but, combined with taller crown angles, they increase darkness from leakage as well as spreading light from the diamond over a wider area). This is a balancing act and it's really hard to generalize since there are so many combination's and style preferences.

On the other hand leakage is always there and doesn't change as you move away from the stone. A stone with an excessive amount of leakage will look darker all the time, regardless of how far away you are. This also affects the fire that you see in a diamond, since the bulk of the fire reflected from the stone is around the perimeter where the crown angles are the steepest and if light is not exiting from those areas there can be no fire from them. There are a lot of balancing acts to be done in a diamond and these are influenced by the need to retain weight and the artistic tastes of the cutter. There really is no "Ideal" diamond cut, since some cutters may prefer a brighter stone and some more fire. The top cuts in diamonds form a rather broad range with some having better fire, some being brighter and some being balanced in between. Of course when you get outside of that range you fall off slowly into the "valley of doom" where the dogs of the diamond world reside. These require better grooming, (or euthanasia), to look their best.

(And I guess an open culet is different than a window? Because I thought the Daussi cushion had an area in the middle where I could see the band through the stone. I'm a fan of open culets in OECs and OMCs, but are they the same things we'd consider 'windows' in coloured stones?)

An open culet is a small facet which is perpendicular to the table, so, yes it is a window through the stone. They were put there originally for a few different reasons. They were probably trying to retain weight and a culet allowed higher weight retention for a given diamond rough. They also helped in keeping the tip of the culet from being broken off as well as for comfort. The rings of that era were a bit shallow compared to the depth of the diamond and so having a flat culet kept the stone from scraping the finger. You may have been able to see the band through the Daussi stone if the pavilion angles were flat enough and you tipped the stone far enough. You may also have been seeing a reflection of the band from the opposite side of the stone, if the crown/ pavilion angles were just right.

Windows in colored stones are very much like an open culet. The angles of the pavilion allow you to see right through the stone making a window.

 

[Michael_E]

Date: 12/8/2009 1:58:25 AM
Author: kenny

So are you saying that every time he posts he comes up higher in Google searches when customers search for diamond vendors?

Sorry to go off topic. That would be clever if it actually worked. Have you tried it, a search I mean ? I did and came up with zip. Getting better Google ratings doesn't do much good when you're pages and pages back. Most people won't go more than three pages deep in Google results and so boosting your position from 20 pages deep to 10 pages deep is like being underwater...you're still sunk if you're objective is to be floating. I like the idea though, it sounds so, umm, strategic.

 

[princesss]

Date: 12/8/2009 12:26:10 PM
Author: Michael_E

Date: 12/8/2009 9:38:36 AM
Author: princesss
So if leakage is around the perimeter, is it caused by the facets being cut so that they don''t reflect the light back at the viewer? For instance, if light entered through the table, it bounced around off of the main facets and then ''leaked'' out around the edges instead of being reflected back to the viewer''s eye? Would that mean that the facets at the bottom (not sure what the proper term for those facets is) are misaligned or the facets near the edge?

The way I understand it, facets act as mirrors for light, and reflect the light back at the same angle they come in (not directly back out, but if it hits one side at an angle, it bounces off at the same angle on the other side, like when you hit a pool ball against the side of the table), which is why you need to line up the facets so precisely to get optimum light return. Is this correct? So if that is true, which poorly-aligned facets would result in leakage and which would result in obstruction? Or is it not that simple?

Alignment is important, but more important is the interaction of the angles of the crown and pavilion. The crown acts like a set of prisms on top of the pavilions mirrors. The leakage that you see in many of the diamond viewers, (ASET, etc.), is not really where you see it, but on the opposite side of the diamond. What you are seeing is a reflection of that leakage, kind of like looking through a periscope, where the light bounces a few times before it leaves the stone and enters your eye.

Obstruction is more straightforward and is most pronounced when looking through the table. This is because the table is flat and any light entering it is influenced mostly by the angles on the pavilion. Looking closely at any round diamond and you''ll notice a brighter round octagon surrounded by the darker area of obstruction. That bright octagon is a reflection of light entering the table from around the sides of the obstruction, (your head). This works because the light entering at a lower angle through the table gets bent as it enters the stone to an angle which allows it to bounce around and exit directly into your eyes. As the pavilion angles, and depth, get larger that bright area gets smaller until it disappears and the entire center looks dark. This, of course, depends on how close your are to the stone, since as you move away from it the obstruction gets smaller. At some point you will be far enough away so that there is no effect from obstruction. Obstruction is also affected by crown angles and table sizes since the angled surfaces on the crown obtain light from areas to the side of the obstruction and so smaller tables can reduce overall darkness from obstruction, (but, combined with taller crown angles, they increase darkness from leakage as well as spreading light from the diamond over a wider area). This is a balancing act and it''s really hard to generalize since there are so many combination''s and style preferences.

On the other hand leakage is always there and doesn''t change as you move away from the stone. A stone with an excessive amount of leakage will look darker all the time, regardless of how far away you are. This also affects the fire that you see in a diamond, since the bulk of the fire reflected from the stone is around the perimeter where the crown angles are the steepest and if light is not exiting from those areas there can be no fire from them. There are a lot of balancing acts to be done in a diamond and these are influenced by the need to retain weight and the artistic tastes of the cutter. There really is no ''Ideal'' diamond cut, since some cutters may prefer a brighter stone and some more fire. The top cuts in diamonds form a rather broad range with some having better fire, some being brighter and some being balanced in between. Of course when you get outside of that range you fall off slowly into the ''valley of doom'' where the dogs of the diamond world reside. These require better grooming, (or euthanasia), to look their best.

(And I guess an open culet is different than a window? Because I thought the Daussi cushion had an area in the middle where I could see the band through the stone. I''m a fan of open culets in OECs and OMCs, but are they the same things we''d consider ''windows'' in coloured stones?)

An open culet is a small facet which is perpendicular to the table, so, yes it is a window through the stone. They were put there originally for a few different reasons. They were probably trying to retain weight and a culet allowed higher weight retention for a given diamond rough. They also helped in keeping the tip of the culet from being broken off as well as for comfort. The rings of that era were a bit shallow compared to the depth of the diamond and so having a flat culet kept the stone from scraping the finger. You may have been able to see the band through the Daussi stone if the pavilion angles were flat enough and you tipped the stone far enough. You may also have been seeing a reflection of the band from the opposite side of the stone, if the crown/ pavilion angles were just right.

Windows in colored stones are very much like an open culet. The angles of the pavilion allow you to see right through the stone making a window.

Thank you! That makes a lot of sense. One of the things I love about diamonds is that there are so many possibilities and so many different "flavours" that you can really find what you love. It does make them a bit harder to learn about, though, since there are rarely "right" and "wrong" answers (especially since what I love the most isn''t the AGS0/H&A that so many PSers adore).

 

[Rockdiamond]

Hi Michael!
Thank you so much for joining the conversation!
I know I'll have a few questions, but I'll need some time to read your posts this far.

To those who complain about the questions I'm asking: On the previous page TWO posters thanked all the participants of this thread because they had learned something about leakage and obstruction.
Personally, I still don;t feel that a clear understanding of how these concepts affects actual diamond buying exists, but the fact people feel they've learned seems good cause for this type of discussion.
I'm sure the subject you mentioned would also be an interesting discussion Laila619- but the reason I have chosen the subjects I have is that they are at the root of a difference of opinion- and an important one ( at least based on the responses)
I'm not asking so that I can understand them better, I'm asking so other readers can.

Date: 12/8/2009 1:00:43 PM
Author: Michael_E

Date: 12/8/2009 1:58:25 AM
Author: kenny

So are you saying that every time he posts he comes up higher in Google searches when customers search for diamond vendors?

Sorry to go off topic. That would be clever if it actually worked. Have you tried it, a search I mean ? I did and came up with zip. Getting better Google ratings doesn't do much good when you're pages and pages back. Most people won't go more than three pages deep in Google results and so boosting your position from 20 pages deep to 10 pages deep is like being underwater...you're still sunk if you're objective is to be floating. I like the idea though, it sounds so, umm, strategic.

Thanks Michael- besides that DiamondsbyLauren has been in the top three results on search engines for "Yellow Diamonds", "Pink Diamonds" as well as many other key phrases for many years.

 

[stone-cold11]

You called a stone with with obstruction issue leakage. This has been point out to you in the last thread too. Is that what you call understanding?

 

[ChunkyCushionLover]

Date: 12/8/2009 1:58:25 AM
Author: kenny

Date: 12/8/2009 1:16:41 AM
Author: ChunkyCushionLover
... I know what he has learned

that backlinks from Pricescope threads help his sites google search rankings ...

David''s company''s name is in the sigline of every one of his posts.

So are you saying that every time he posts he comes up higher in Google searches when customers search for diamond vendors?

Wow.

No wonder he keeps conversations going on for ever and ever by asking the same question over and over and acting confused.
Smart man - and as long as he is polite and follows PS rules he can exploit PS for his gain forever with impunity.

It kind of makes me feel like a sucker for even talking to him.

CCL, I''m sure glad that you didn''t boycott this thread.
You have let some sunlight in and now we see what''s really going on - and actually this explains the repetition problem.
Boycotting would just let it continue unexposed and unchallenged.

Backlinks help especially from sites like Pricescope with High PR ratings.
Every RD post has his tagline to his website as a hyperlink. I think that non paying advertisers should not be allowed to enter a hyperlink in every post, as RD is exploiting this.
If you google search for "Daussi Cushion" you will see that DBL is on the first page (5 down) and his videos are in several places on the first page of organic listings.
The backlinks from PS help his overall homepage score and this counts towards any search terms not just the mainstream ones where DBL doesn''t rank very high.

 

[Rockdiamond]

Date: 12/7/2009 10:37:29 PM
Author: Michael_E

Date: 12/7/2009 8:09:39 PM
Author: princesss
Basically, if I look at a stone and think, ''I could drive a truck through that window!'' it''s leakage. If it''s dark, but I can''t see the finger under the stone, it''s obstruction.

Unfortunately this is only correct for colored stones and not diamonds. Unless a diamond is an absolute train wreck of cutting, then you will never see a window through it or be able to see your finger, (even if it leaks like a sieve). One thing that has gone missing in this discussion is that darkness from ''leakage'' occurs in different areas of a round brilliant diamond than darkness from ''obstruction''. In even moderately cut diamonds which have significant leakage, it we be mostly evident around the perimeter of the stone and not under the table. Any darkness under the table will nearly always be caused by ''obstruction'' due to the cut being too deep. IN shallow stones any darkness under the table comes from increasing reflections coming from low on the horizon. I think that one of you guy''s with some ''leaky'' diamonds ought to toss up some pictures and label the leakage areas so that the meaning and location of this effect becomes more clear for everyone who isn''t clear about it.

Interesting Michael!
I''ve seen so many cases of folks being warned against leakage in the table- however your post seems to indicate differently.

I am loath to again ask this question, which never seems to find a easy answer:
The Daussi cushions have a high degree of contrast- referred to here as a "bow-tie".
People have stated categorically that this is "obstruction"
If the diamond is being viewed in a position that places the head ( or camera) in a position where it''s impossible to obstruct the light, how is that bow tie caused by obstruction? You''ll see the dark area regardless of where your head is....

I agree that photos showing leakage will be a big help to this conversation.

For me, leakage is never good. I do understand how for some leakage wouldn''t be a problem but it''s a personal hate of mine. I''m confused as to how it can ever make a diamond look good but I guess beauty is in the eye of the beholder?

LD- I really meant what I said, you could certainly be effective working in the gem trade as it''s clear to me you really do have a good grasp on how to buy effectively.
As such, the statement you made indicates to me how "wrong" the whole term leakage is, as it''s being used.
I don''t believe any modern cut diamond has zero leakage. Put another way, every diamond has some darker areas. Personally I don''t feel it''s important if one calls them "leakage" or "obstruction". But all diamonds have some darkness along with the flash.
Some of the facets will point away from your eye, or reflect darkness since they can''t all point in the same direction- this is an essential element in "sparkle"
What this means is that ALL your favorite diamonds exhibit some dark areas- be it "leakage" or obstruction..
I''m sure they do'';t have anything negative associated with this- but there again is the problem with these terms, and how they are used.