Assessing Cut for the Online Diamond Purchase

[strmrdr]

Date: 5/13/2009 5:17:00 PM
Author: Regular Guy
bump (as Serg, and us regular folk, are waiting for the plain english reply)...

John is out of town and with limited internet time.
I want to start another thread to discuss those questions in depth but am trying to decide if I should wait for Sir John to get back since it was addressed to him.

 

[iraweissman]

Hi Purrfect Pear. What I wrote is 100% true, and yet your concern is true as well. If a black inclusion reaches the surface in any meaningful way other than a hairline fissure, deep boiling (in Hebrew, the slang is "amuka" which simply means "deep") the result will leave a cavity. Many buyers from the largest chains (Sterling, Zales, Helzberg [they''re crazy about this]) will refuse any stone with an "open" or noticeable cavity on the surface. Because of this, large manufacturers like Leo Schachter simply won''t boil the diamonds that will result in noticeable cavities.

Many diamonds naturally have cavities anyway without the boiling. It''s just what happens if the diamond is cut so that a part of an internal gaseous (not solid) inclusion in the rough is now left on the surface of the cut diamond.

So while there is definitely a stigma of "opens" in the industry, there is most definitely not a stigma of boiled diamonds.

I have seen many diamonds with internal black inclusions that only have a microscopic (and translucent) continuation of the inclusion to the surface successfully cleaned with a good long deep boiling. The resulting "open" on the surface is microscopic. Many times, if the black inclusion is thin enough, it can almost disappear completely -- not even leaving behind a clear crystal.

As I said, there is absolutely no stigma attached to this practice whatsoever. Every diamond manufacturer does it (if they deal in diamonds that will ever have black inclusions).

Date: 5/12/2009 5:02:09 PM
Author: purrfectpear
Interesting comment on Weissman''s site about clarity enhancement:


1) Deep Boiling:This is the only type of clarity enhancement that is sanctioned by the GIA. This involves boiling the diamond under deep pressure in a special acidic solution. This procedure only works on diamonds whose inclusions are black and reach the surface. If the inclusion cavity does not reach the outer surface of the finished cut diamond, then the acid has no way of penetrating the inclusion. Likewise, deep boiling does not fill in the cavity, it simply removes the black compound that''s filling it. So at best this procedure can remove a very noticeable black inclusion and replace it with a slightly translucent white inclusion. This procedure is so commonplace and cheap that most diamond manufacturers simply deep boil an entire production of diamonds before sorting to be sure they have removed any black inclusions that could be removed. There is no stigma whatsoever attached to this treatment.

Experts, truth or not? I''m well aware of boiling diamonds. I''m not aware that ''most'' diamonds are boiled, and I would think that there ''would'' be some stigma in having a void on the surface of your diamond. Your take?

 

[Garry H (Cut Nut)]

Date: 5/14/2009 3:13:12 AM
Author: iraweissman

Many diamonds naturally have cavities anyway without the boiling. It''s just what happens if the diamond is cut so that a part of an internal gaseous (not solid) inclusion in the rough is now left on the surface of the cut diamond.

Gas inside a diamond crystal is impossible because there are no gases at the pressure required for diamonds to grow.

Boiling is a normal process PP - as much as anything to remove metals remnants on the diamond. Much or Ira''s writting is accurate.

 

[iraweissman]

removed accidental double post

 

[iraweissman]

Hi Garry. What you say makes sense, but when I was taught not to let the diamond get too hot when it''s on the wheel lest it explode, I always assumed it was because of gas trapped inside inclusions. Do you know the correct reason?

Date: 5/14/2009 3:20:26 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 3:13:12 AM

Author: iraweissman


Many diamonds naturally have cavities anyway without the boiling. It''s just what happens if the diamond is cut so that a part of an internal gaseous (not solid) inclusion in the rough is now left on the surface of the cut diamond.

Gas inside a diamond crystal is impossible because there are no gases at the pressure required for diamonds to grow.


Boiling is a normal process PP - as much as anything to remove metals remnants on the diamond. Much or Ira''s writting is accurate.

 

[Garry H (Cut Nut)]

Date: 5/14/2009 3:58:12 AM
Author: iraweissman
Hi Garry. What you say makes sense, but when I was taught not to let the diamond get too hot when it''s on the wheel lest it explode, I always assumed it was because of gas trapped inside inclusions. Do you know the correct reason?

Date: 5/14/2009 3:20:26 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 3:13:12 AM

Author: iraweissman


Many diamonds naturally have cavities anyway without the boiling. It''s just what happens if the diamond is cut so that a part of an internal gaseous (not solid) inclusion in the rough is now left on the surface of the cut diamond.

Gas inside a diamond crystal is impossible because there are no gases at the pressure required for diamonds to grow.


Boiling is a normal process PP - as much as anything to remove metals remnants on the diamond. Much or Ira''s writting is accurate.

More likely just simple differential expansion between different minerals - you could search stuff like this to learn more
http://www.springerlink.com/content/l887217241w58401/

there should also be mineralogic info on coefficients of expansion - it is the differences in pyropes and garnets and such common inclusions that cause the problems.

 

[diagem]

Date: 5/14/2009 4:11:06 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 3:58:12 AM
Author: iraweissman
Hi Garry. What you say makes sense, but when I was taught not to let the diamond get too hot when it''s on the wheel lest it explode, I always assumed it was because of gas trapped inside inclusions. Do you know the correct reason?

Date: 5/14/2009 3:20:26 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 3:13:12 AM

Author: iraweissman


Many diamonds naturally have cavities anyway without the boiling. It''s just what happens if the diamond is cut so that a part of an internal gaseous (not solid) inclusion in the rough is now left on the surface of the cut diamond.

Gas inside a diamond crystal is impossible because there are no gases at the pressure required for diamonds to grow.


Boiling is a normal process PP - as much as anything to remove metals remnants on the diamond. Much or Ira''s writting is accurate.

More likely just simple differential expansion between different minerals - you could search stuff like this to learn more
http://www.springerlink.com/content/l887217241w58401/

there should also be mineralogic info on coefficients of expansion - it is the differences in pyropes and garnets and such common inclusions that cause the problems.

There is an old practice (well, not so old as it was [and still is] practiced by manufacturers today) to laser drill clear bubbles in the rough prior to sawing them.

Most manufacturers think like Ira (gas), so they attempt to release the ''gas'' in the bubble by penetrating it with the laser hole.

I never practiced it As I dont believe in it

)..., but I do know that some bubble''s show tremendous stress in a polariscope test. And thats what freaks the manufacturers out.

 

[Serg]

GiaGem,


Re: to laser drill clear bubbles in the rough prior to sawing them.

“Bubbles” are diamond crystals with other crystal-lattice [crystallographic] orientation inside rough diamond . Because mechanical sawing is possible only in angle range 0-15 degree( even less) and “bubbles” have different orientation, sawing disk usually can not pass “bubbles’. If you want sawing through "bubbles", you need use laser sawing.
Because “Bubbles” have different crystallographic orientation( from main rough), it create stress which you can see in polarization light

 

[diagem]

Date: 5/14/2009 5:55:32 AM
Author: Serg
GiaGem,


Re: to laser drill clear bubbles in the rough prior to sawing them.

“Bubbles” are diamond crystals with other crystal-lattice [crystallographic] orientation inside rough diamond . Because mechanical sawing is possible only in angle range 0-15 degree( even less) and “bubbles” have different orientation, sawing disk usually can not pass “bubbles’. If you want sawing through ''bubbles'', you need use laser sawing.
Because “Bubbles” have different crystallographic orientation( from main rough), it create stress which you can see in polarization light

No Serg..., I am talking about blade/mechanical sawable bubble''s..., pure round shaped.

 

[Garry H (Cut Nut)]

Date: 5/14/2009 6:23:07 AM
Author: DiaGem

Date: 5/14/2009 5:55:32 AM
Author: Serg
GiaGem,


Re: to laser drill clear bubbles in the rough prior to sawing them.

“Bubbles” are diamond crystals with other crystal-lattice [crystallographic] orientation inside rough diamond . Because mechanical sawing is possible only in angle range 0-15 degree( even less) and “bubbles” have different orientation, sawing disk usually can not pass “bubbles’. If you want sawing through ''bubbles'', you need use laser sawing.
Because “Bubbles” have different crystallographic orientation( from main rough), it create stress which you can see in polarization light

No Serg..., I am talking about blade/mechanical sawable bubble''s..., pure round shaped.

I have never seen a round diamond spherical inclusion DG?
I have seen disc shapes like those here in the 115X view

 

[diagem]

Date: 5/14/2009 6:30:23 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 6:23:07 AM
Author: DiaGem

Date: 5/14/2009 5:55:32 AM
Author: Serg
GiaGem,


Re: to laser drill clear bubbles in the rough prior to sawing them.

“Bubbles” are diamond crystals with other crystal-lattice [crystallographic] orientation inside rough diamond . Because mechanical sawing is possible only in angle range 0-15 degree( even less) and “bubbles” have different orientation, sawing disk usually can not pass “bubbles’. If you want sawing through ''bubbles'', you need use laser sawing.
Because “Bubbles” have different crystallographic orientation( from main rough), it create stress which you can see in polarization light

No Serg..., I am talking about blade/mechanical sawable bubble''s..., pure round shaped.

I have never seen a round diamond spherical inclusion DG?
I have seen disc shapes like those here in the 115X view

I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not ''perfect sphere''s).
But in any case..., they are/were sawable via blade sawing.

 

[Garry H (Cut Nut)]

Garnet dodecahedra

 

[diagem]

Date: 5/14/2009 6:48:29 AM
Author: Garry H (Cut Nut)
Garnet dodecahedra

Colorless??

 

[Garry H (Cut Nut)]

Date: 5/14/2009 7:04:35 AM
Author: DiaGem

Date: 5/14/2009 6:48:29 AM
Author: Garry H (Cut Nut)
Garnet dodecahedra

Colorless??

Diamond dodecahedra
or rarely
http://minerals.caltech.edu/files/Visible/garnet/Grossular_Asbestos_colorless.jpg
and http://www.gemsandjewelryrus.com/Colorless_garnet.jpg

 

[Serg]

Date: 5/14/2009 6:23:07 AM
Author: DiaGem

Date: 5/14/2009 5:55:32 AM

Author: Serg

GiaGem,



Re: to laser drill clear bubbles in the rough prior to sawing them.


“Bubbles” are diamond crystals with other crystal-lattice [crystallographic] orientation inside rough diamond . Because mechanical sawing is possible only in angle range 0-15 degree( even less) and “bubbles” have different orientation, sawing disk usually can not pass “bubbles’. If you want sawing through ''bubbles'', you need use laser sawing.

Because “Bubbles” have different crystallographic orientation( from main rough), it create stress which you can see in polarization light

No Serg..., I am talking about blade/mechanical sawable bubble''s..., pure round shaped.

Yes, I am speaking exactly about same. of course I do not believe in pure round shaped. usually shape is between octahedron( or dodecahedra) and ellipsoid. But shape does not matter at all. Only crystallographic orientation is important.

 

[Serg]

re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not 'perfect sphere's).
But in any case..., they are/were sawable via blade sawing.

It is mean what difference between crystallographic orientation was small. just it.
If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.

You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.
for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

 

[diagem]

Date: 5/14/2009 7:31:41 AM
Author: Serg
re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not ''perfect sphere''s).
But in any case..., they are/were sawable via blade sawing.

It is mean what difference between crystallographic orientation was small. just it.
If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.

You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.
for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

Ok..., so how do you explain I ended up with two halves and two ''empty'' holes where the bubble was?

 

[Garry H (Cut Nut)]

Date: 5/14/2009 8:09:27 AM
Author: DiaGem

Date: 5/14/2009 7:31:41 AM
Author: Serg
re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not 'perfect sphere's).
But in any case..., they are/were sawable via blade sawing.

It is mean what difference between crystallographic orientation was small. just it.
If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.

You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.
for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

Ok..., so how do you explain I ended up with two halves and two 'empty' holes where the bubble was?

the crystal was sawn thru and dropped out - quite seriously as a not very bright geologist (35 years ago) - gas is not possible in something that grows at diamond pressure - there is no gas that would not become solid - even liquid would have to be impossible (I think)

 

[diagem]

Date: 5/14/2009 8:14:18 AM
Author: Garry H (Cut Nut)

Date: 5/14/2009 8:09:27 AM
Author: DiaGem

Date: 5/14/2009 7:31:41 AM
Author: Serg
re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not ''perfect sphere''s).
But in any case..., they are/were sawable via blade sawing.

It is mean what difference between crystallographic orientation was small. just it.
If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.

You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.
for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

Ok..., so how do you explain I ended up with two halves and two ''empty'' holes where the bubble was?

the crystal was sawn thru and dropped out - quite seriously as a not very bright geologist (35 years ago) - gas is not possible in something that grows at diamond pressure - there is no gas that would not become solid - even liquid would have to be impossible (I think)

Garry..., I never said gas..., I actually agreed with you on that!
But could it be empty bubble''s? I doubt that every time the saw blade goes through the ''different crystallographic'' inclusion they drop out of the main stone....

 

[Serg]

Date: 5/14/2009 8:41:58 AM
Author: DiaGem

Date: 5/14/2009 8:14:18 AM

Author: Garry H (Cut Nut)

Date: 5/14/2009 8:09:27 AM

Author: DiaGem

Date: 5/14/2009 7:31:41 AM

Author: Serg

re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not ''perfect sphere''s).

But in any case..., they are/were sawable via blade sawing.


It is mean what difference between crystallographic orientation was small. just it.

If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.


You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.

for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

Ok..., so how do you explain I ended up with two halves and two ''empty'' holes where the bubble was?

the crystal was sawn thru and dropped out - quite seriously as a not very bright geologist (35 years ago) - gas is not possible in something that grows at diamond pressure - there is no gas that would not become solid - even liquid would have to be impossible (I think)

Garry..., I never said gas..., I actually agreed with you on that!

But could it be empty bubble''s? I doubt that every time the saw blade goes through the ''different crystallographic'' inclusion they drop out of the main stone....

re:I doubt that every time the saw blade goes through the ''different crystallographic'' inclusion they drop out of the main stone....
Each time? how is often it happened? I saw sawing ''bubbles'' several times. I never saw holes after sawing. I saw how blade become bent when you try sawing ''bubbles''.

 

[diagem]

Date: 5/14/2009 10:02:15 AM
Author: Serg

Date: 5/14/2009 8:41:58 AM
Author: DiaGem

Date: 5/14/2009 8:14:18 AM

Author: Garry H (Cut Nut)

Date: 5/14/2009 8:09:27 AM

Author: DiaGem

Date: 5/14/2009 7:31:41 AM

Author: Serg

re:I have...., and I have sawn right through them as well resulting in two halves spheres...., (ok..., maybe not ''perfect sphere''s).

But in any case..., they are/were sawable via blade sawing.


It is mean what difference between crystallographic orientation was small. just it.

If difference between rystallographic orientation is big, you can not sawing by mechanical blade. before you touch “Bubbles” by blade during sawing you do not know how is big difference.


You need reduce sawing speed if blade touch “diamond Bubbles”, depends from angle between crystallographic orientation . If angle between crystallographic orientation is too big, you need wait days or years.

for “non diamond Bubbles”, you do not need reduce speed. there are o lot of other minerals could be in diamond

Ok..., so how do you explain I ended up with two halves and two ''empty'' holes where the bubble was?

the crystal was sawn thru and dropped out - quite seriously as a not very bright geologist (35 years ago) - gas is not possible in something that grows at diamond pressure - there is no gas that would not become solid - even liquid would have to be impossible (I think)

Garry..., I never said gas..., I actually agreed with you on that!

But could it be empty bubble''s? I doubt that every time the saw blade goes through the ''different crystallographic'' inclusion they drop out of the main stone....

re:I doubt that every time the saw blade goes through the ''different crystallographic'' inclusion they drop out of the main stone....
Each time? how is often it happened? I saw sawing ''bubbles'' several times. I never saw holes after sawing. I saw how blade become bent when you try sawing ''bubbles''.

Serge..., many times...

I saw some of the blades bent too..., but that after attempting to saw through a more identifiable inclusion.