Cut Adviser Question

[zman8]

So I''m getting a stone replaced. The original stone ranked around a 1.5 on the cut adviser, and the new stone is a 2.2.

Is this a negligible difference to the untrained eye, am I being obsessive compulsive, ie, should I really care?

Thanks

 

[Lorelei]

Hi zman,

The HCA isn''t used for selection but elimination. No way to tell how the diamonds compare from the HCA score so if you could post the proportions of the new stone we can take a look. It might be ok even as it scored over 2, do you have Idealscope images?

 

[zman8]

Date: 4/25/2009 7:50:03 AM
Author: Lorelei
Hi zman,


The HCA isn''t used for selection but elimination. No way to tell how the diamonds compare from the HCA score so if you could post the proportions of the new stone we can take a look. It might be ok even as it scored over 2, do you have Idealscope images?

Original Stone:
1.2 VS2 G 6.94-6.96x4.2
56 60.4 34.2 40.6

New Stone:
1.25 VS1 G 6.86-6.87x4.27
57 62.2 35.5 40.8


Thanks

 

[stone-cold11]

Do you have the idealscope image of the replacement stone?

 

[zman8]

Date: 4/25/2009 8:03:50 AM
Author: Stone-cold11
Do you have the idealscope image of the replacement stone?

No I do not.

Its a sad story...I bought the original stone online and the fiancee lost it

So this is the insured replacement. I looked at the new stone yesterday under the microscope and it looked great.

I'm just wondering if there will be any truly visible change in "sparklyness" of the diamond.

Note that I am more of a "by the numbers guy" and less able to see any differance.

 

[Lorelei]

Date: 4/25/2009 7:55:10 AM
Author: zman8

Date: 4/25/2009 7:50:03 AM
Author: Lorelei
Hi zman,


The HCA isn't used for selection but elimination. No way to tell how the diamonds compare from the HCA score so if you could post the proportions of the new stone we can take a look. It might be ok even as it scored over 2, do you have Idealscope images?

Original Stone:
1.2 VS2 G 6.94-6.96x4.2
56 60.4 34.2 40.6

New Stone:
1.25 VS1 G 6.86-6.87x4.27
57 62.2 35.5 40.8


Thanks

Thank you! It is a tricky combo to call without images for the crown and pavilion angles, it is entering steep deep zone and could leak light, but if it looks ok to you - check it out closely to see if you notice any dark areas on top of the diamond or a dark ring around the table, if not it might be ok.

Do you have any others in mind?

 

[zman8]

Date: 4/25/2009 8:13:27 AM
Author: Lorelei

Date: 4/25/2009 7:55:10 AM

Author: zman8

Date: 4/25/2009 7:50:03 AM

Author: Lorelei

Hi zman,



The HCA isn''t used for selection but elimination. No way to tell how the diamonds compare from the HCA score so if you could post the proportions of the new stone we can take a look. It might be ok even as it scored over 2, do you have Idealscope images?

Original Stone:

1.2 VS2 G 6.94-6.96x4.2

56 60.4 34.2 40.6


New Stone:

1.25 VS1 G 6.86-6.87x4.27

57 62.2 35.5 40.8



Thanks

Thank you! It is a tricky combo to call without images for the crown and pavilion angles, it is entering steep deep zone and could leak light, but if it looks ok to you - check it out closely to see if you notice any dark areas on top of the diamond or a dark ring around the table, if not it might be ok.


Do you have any others in mind?

Well it needs to be of similar kind and quality as the original.

Should I go back to the jeweler and ask for a different stone?

Would the jewler be able to send me an idealscope image of the diamond? Should I look at the diamond under an idealscope (and if so, what am I looking for?)?

 

[Lorelei]

Date: 4/25/2009 9:34:25 AM
Author: zman8

Date: 4/25/2009 8:13:27 AM
Author: Lorelei

Date: 4/25/2009 7:55:10 AM

Author: zman8

Date: 4/25/2009 7:50:03 AM

Author: Lorelei

Hi zman,



The HCA isn''t used for selection but elimination. No way to tell how the diamonds compare from the HCA score so if you could post the proportions of the new stone we can take a look. It might be ok even as it scored over 2, do you have Idealscope images?

Original Stone:

1.2 VS2 G 6.94-6.96x4.2

56 60.4 34.2 40.6


New Stone:

1.25 VS1 G 6.86-6.87x4.27

57 62.2 35.5 40.8



Thanks

Thank you! It is a tricky combo to call without images for the crown and pavilion angles, it is entering steep deep zone and could leak light, but if it looks ok to you - check it out closely to see if you notice any dark areas on top of the diamond or a dark ring around the table, if not it might be ok.


Do you have any others in mind?

Well it needs to be of similar kind and quality as the original.

Should I go back to the jeweler and ask for a different stone?

Would the jewler be able to send me an idealscope image of the diamond? Should I look at the diamond under an idealscope (and if so, what am I looking for?)?

It appears that it is unusual for a store jeweller to have access to an Idealscope, you could however order your own for $25. This is an iffy angle combo to me, it is possible the diamond could leak light and show this in looking dark at times face up. Idealscope are straightforward to use and this chart shows you what to look for, you can see the paler patches which indicate leakage. Once you know what to look for then it is reasonably easy to interpret these images.

http://www.ideal-scope.com/using_reference_chart.asp

I would ask the jeweller what else he can show you with less steep angles, I would suggest 34- 35 crown angle and 40.6 - 40.8 pavilion angle. Even 34 crown and 41 pavilion can be a good balance for each other.

 

[stone-cold11]

Date: 4/25/2009 8:06:45 AM
Author: zman8

Date: 4/25/2009 8:03:50 AM

Author: Stone-cold11

Do you have the idealscope image of the replacement stone?

No I do not.

Its a sad story...I bought the original stone online and the fiancee lost it

So this is the insured replacement. I looked at the new stone yesterday under the microscope and it looked great.
I'm just wondering if there will be any truly visible change in 'sparklyness' of the diamond.
Note that I am more of a 'by the numbers guy' and less able to see any differance.

Sorry to hear that. Try and find another of similar combo to your original stone I would say, safer. Also, get an Idealscope. Good Luck. Are you still working with JA for your replacement stone or with your insurance's jeweler?

 

[zman8]

But is the leakage noticeable to the untrained eye, or is it just something that I may be obsessing over?

Also, I looked at the stone under the microscope at the jewler and could actually see the arrows in the stone would that imply one way or the other whether leakage occurs?

 

[zman8]

Date: 4/25/2009 10:19:07 AM
Author: Stone-cold11

Date: 4/25/2009 8:06:45 AM

Author: zman8

Date: 4/25/2009 8:03:50 AM


Author: Stone-cold11


Do you have the idealscope image of the replacement stone?

No I do not.


Its a sad story...I bought the original stone online and the fiancee lost it

So this is the insured replacement. I looked at the new stone yesterday under the microscope and it looked great.

I''m just wondering if there will be any truly visible change in ''sparklyness'' of the diamond.

Note that I am more of a ''by the numbers guy'' and less able to see any differance.

Sorry to hear that. Try and find another of similar combo to your original stone I would say, safer. Also, get an Idealscope. Good Luck. Are you still working with JA for your replacement stone or with your insurance''s jeweler?

Insurance jewler, Boone and Sons in DC

 

[stone-cold11]

Date: 4/25/2009 10:19:55 AM
Author: zman8

But is the leakage noticeable to the untrained eye, or is it just something that I may be obsessing over?

Also, I looked at the stone under the microscope at the jewler and could actually see the arrows in the stone would that imply one way or the other whether leakage occurs?

Because the numbers for the angles are average of 8 facets and rounded, there is a likely change that a pair of the facets might be off resulting in significant leakage. So IS is just to confirm it is not so.

 

[Lorelei]

Date: 4/25/2009 10:19:55 AM
Author: zman8


But is the leakage noticeable to the untrained eye, or is it just something that I may be obsessing over?

Also, I looked at the stone under the microscope at the jewler and could actually see the arrows in the stone would that imply one way or the other whether leakage occurs?

It is possible it could show to the untrained eye or not, there is much info we are missing and assuming these are GIA numbers they are rounded anyway which makes it even more difficult to tell. Arrow patterning is not related to performance as such or leakage, the proportions are what counts.

What I would do is to ask the jeweller to show you another diamond with a 'safer' angle range as I suggested above, then compare this one to the one with the less ' risky' angles, then that could be the clincher.

 

[zman8]

Date: 4/25/2009 10:25:06 AM
Author: Lorelei

Date: 4/25/2009 10:19:55 AM

Author: zman8



But is the leakage noticeable to the untrained eye, or is it just something that I may be obsessing over?


Also, I looked at the stone under the microscope at the jewler and could actually see the arrows in the stone would that imply one way or the other whether leakage occurs?

It is possible it could show to the untrained eye or not, there is much info we are missing and assuming these are GIA numbers they are rounded anyway which makes it even more difficult to tell. Arrow patterning is not related to performance as such or leakage, the proportions are what counts.


What I would do is to ask the jeweller to show you another diamond with a ''safer'' angle range as I suggested above, then compare this one to the one with the less '' risky'' angles, then that could be the clincher.

So if I stop by the store today, what should I ask/look for in the current diamond, and in a similar diamond?

Also, it is a GIA diamond.

 

[Lorelei]

Check it out as I mentioned above, what you are looking for are dark dull areas when viewing the diamond face up, sometimes you can see a dark ring around the table.

You can use these numbers as a guide to help you find a well cut round if needed.

depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

From expert John Pollard,
"As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here''s a "Cliff''s Notes" for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA "EX" in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35)."

 

[zman8]

Date: 4/25/2009 10:32:20 AM
Author: Lorelei
Check it out as I mentioned above, what you are looking for are dark dull areas when viewing the diamond face up, sometimes you can see a dark ring around the table.


You can use these numbers as a guide to help you find a well cut round if needed.


depth - 60 - 62% - although my personal preference is to allow up to 62.4%

table - 54- 57%

crown angle - 34- 35 degrees

pavilion angle - 40.6- 41 degrees

girdle - avoid extremes, look for thin to slightly thick, thin to medium etc

polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

From expert John Pollard,

''As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here''s a ''Cliff''s Notes'' for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA ''EX'' in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).''

I''m going to recheck the diamond today. But if I can''t see anything should I worry? (ie eye clean vs. mind clean)

Is this still a good diamond (even though it may not be PS perfect)?

 

[HornAround]

Date: 4/25/2009 10:32:20 AM
Author: Lorelei

Check it out as I mentioned above, what you are looking for are dark dull areas when viewing the diamond face up, sometimes you can see a dark ring around the table.

You can use these numbers as a guide to help you find a well cut round if needed.

depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

From expert John Pollard,
''As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here''s a ''Cliff''s Notes'' for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA ''EX'' in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).''

Excuse me for asking, but isn''t thin to thick an extreme girdle measure? Just trying to clarify.

 

[Lorelei]

Date: 4/25/2009 12:27:31 PM
Author: HornAround

Date: 4/25/2009 10:32:20 AM
Author: Lorelei




Check it out as I mentioned above, what you are looking for are dark dull areas when viewing the diamond face up, sometimes you can see a dark ring around the table.

You can use these numbers as a guide to help you find a well cut round if needed.

depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

From expert John Pollard,
'As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here's a 'Cliff's Notes' for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA 'EX' in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).'

Excuse me for asking, but isn't thin to thick an extreme girdle measure? Just trying to clarify.

No problem Horn, it is thin to slightly thick which is different from thin to thick.

 

[stone-cold11]

Date: 4/25/2009 12:27:31 PM
Author: HornAround
Excuse me for asking, but isn''t thin to thick an extreme girdle measure? Just trying to clarify.

Slightly thick is not thick.

 

[Lorelei]

Date: 4/25/2009 12:27:14 PM
Author: zman8

Date: 4/25/2009 10:32:20

I''m going to recheck the diamond today. But if I can''t see anything should I worry? (ie eye clean vs. mind clean)

Is this still a good diamond (even though it may not be PS perfect)?

What I would suggest, if you like the diamond - make the sale final on it checking out with an independant appraisal, if you choose an appraiser who is skilled in evaluating cut then this could be well worth doing. It could be a good diamond but the angle range makes me wary and without seeing any images of the diamond, I don''t want to mislead you by saying oh yes it should be fine when there is a chance it could show leakage.

Here is a tool you can use to find an appraiser in your area.

https://www.pricescope.com/appr_list.aspx