Real life H&A''s vs ideal-scope test

[Garry H (Cut Nut)]

We have just had a shipment in from Antwerp; my diamond buying staff rejected 2/3rds of the parcel which must be returned at our cost.

60% were rejected because the Ideal-Scope was not good enough (less than 10% were rejected for color and clarity).

I just looked through the stones we rejected; more than ½ have good to excellent Hearts and Arrows patterns but none of the regulars here would be happy with their Ideal-scope images.

Many people believe that H&A’s are the ultimate Ideal-Cut diamonds, but my (very small 70 odd stone) survey showed that more than ½ of these H&A’s failed an Idealscope examination.

(The diamonds were pre selected with an Ideal-Scope by the supplier, and were all meant to be D-G VS-SI1. Our minimum standard is H SI2+. If they were not preselected we would have had an even higher rejection rate with the ideal-scope - and probably would have had less H&A''s too)

 

[noobie]

Date: 11/23/2004 2:54

7 AM
Author:Garry H (Cut Nut)

60% were rejected because the Ideal-Scope was not good enough (less than 10% were rejected for color and clarity).

The diamonds were pre selected with an Ideal-Scope by the supplier,

Curious as to why the rejection rate rate was so high if the supplier was screeneing with the IS.
Looser standards?
Improper Use?

 

[strmrdr]

sounds like what niceice was talking bout the other day.
The cutters are cheating to get good numbers.

edit to add> cheating in the real world meaning not cheating as defined by Brian and other cutters :}

 

[JohnQuixote]

Date: 11/23/2004 2:54

7 AM
Author:Garry H (Cut Nut)

We have just had a shipment in from Antwerp; my diamond buying staff rejected 2/3rds of the parcel which must be returned at our cost.

60% were rejected because the Ideal-Scope was not good enough (less than 10% were rejected for color and clarity).

I just looked through the stones we rejected; more than ½ have good to excellent Hearts and Arrows patterns but none of the regulars here would be happy with their Ideal-scope images.

Many people believe that H&A’s are the ultimate Ideal-Cut diamonds, but my (very small 70 odd stone) survey showed that more than ½ of these H&A’s failed an Idealscope examination.

(The diamonds were pre selected with an Ideal-Scope by the supplier, and were all meant to be D-G VS-SI1. Our minimum standard is H SI2+. If they were not preselected we would have had an even higher rejection rate with the ideal-scope - and probably would have had less H&A's too)

Hi Garry. Last night I stocked up on Fosters for Turkey-day and thought of you.

A couple of questions: Would you clarify what you mean by failing the IS test? Can you indicate what level of leakage on this page (from your site) you observed in those you didn't like?

I feel your pain in a different way...I see many stones marketed as Hearts & Arrows which are not cut with the degree of physical symmetry to be called "True" H&A in my book. Most often, when the patterns are (even slightly) distorted due to facet yaw (what cutters call cheating

), they can seriously leak light while still being an "almost true" H&A pattern. I am used to seeing examples like that - but I have not seen many "true" H&A with ideal proportions which fail IdealScope.

If you haven't already sent them back it would be helpful to see what you mean (IdealScope images). I see on your website where you have posted examples of poorly cut H&A that still have good IS images. Can you post some "True" H&A patterns which have poor IS images here? It would be especially helpful if you can include proportion details.

I don't necessarily believe H&A cuts are more beautiful than non H&A, but the appealing quality of H&A for those who choose them is precision and - for our purposes here - consistency. I am used to seeing solid consistency in IdealScope images from those with what I consider "true" patterning - it would be instructive to analyze some like you have mentioned! I think NiceIce was talking about "loosened" standards in this sense a week or so ago... None of us want standards diluted.

 

[Rhino]

Doesn''t surprise me mate. At the last Vegas show I''d say that the ratio was worse (conicides with what you''re saying). Of note was a particular manufacturer who was also featuring idealscopes!!! They had proportions written down on each of the diamonds and every one had crown/pavilion angles listed as being in the neighborhood of 34-34.5 with pavilions of 40.7-40.9. Now ... I happen to be familiar with what those proportions should look like and everyone of em had rings of white under the table.

There was no way those stones were even the proportions they were stating. Of all the suppliers at the show Gary, and all those featuring H&A''s I think I only found 1 new source whose inventory was 50/50 (50% beauties vs 50% so so). I am an H&A advocate but as you state ... just because it''s H&A doesn''t necessarily mean it''s going to have superior brilliance.

 

[JohnQuixote]

Date: 11/23/2004 10:45:30 AM
Author: Rhino
Doesn''t surprise me mate. At the last Vegas show I''d say that the ratio was worse (conicides with what you''re saying). Of note was a particular manufacturer who was also featuring idealscopes!!! They had proportions written down on each of the diamonds and every one had crown/pavilion angles listed as being in the neighborhood of 34-34.5 with pavilions of 40.7-40.9. Now ... I happen to be familiar with what those proportions should look like and everyone of em had rings of white under the table.

There was no way those stones were even the proportions they were stating. Of all the suppliers at the show Gary, and all those featuring H&A''s I think I only found 1 new source whose inventory was 50/50 (50% beauties vs 50% so so). I am an H&A advocate but as you state ... just because it''s H&A doesn''t necessarily mean it''s going to have superior brilliance.

RhinoKnight... We''re on the same page here. Generally if the proportions are those you listed and the H&A precision is top-notch the IS images that follow are pretty darn good.

 

[denverappraiser]

Garry,

I think you are pointing out an example of a serious problem with the IS. Assuming that your supplier is not deliberately trying to stick you with unwanted merchandise, this all means that the requirements to pass their tests are importantly different from the requirements imposed by you and your staff. It sounds to me like the problem is with properly explaining what constitutes an acceptable IS image and possibly a problem of properly training both the staff and the suppliers in consistent use of the instrument so that they are both seeing the same image. IMO, the IS would be a much more useful tool for dealers if you were to invent a language for describing the various attributes that could then be applied by a trained observer. This is conspicuously close to an IS cut grading scale, something you’ve been avoiding for good reason, but perhaps there is some common ground where it’s possible to concisely describe attributes that you are going to reject and others that you are particularly seeking. Perhaps a system similar to what is used to describe pearls is in order.

Neil Beaty, GG ISA
Independent Appraisals in Denver

 

[Paul-Antwerp]

Garry,

It seems that you need an eye in Antwerp.

Live long,

 

[Rhino]

Date: 11/23/2004 10:56:16 AM
Author: JohnQuixote

Date: 11/23/2004 10:45:30 AM
Author: Rhino
Doesn''t surprise me mate. At the last Vegas show I''d say that the ratio was worse (conicides with what you''re saying). Of note was a particular manufacturer who was also featuring idealscopes!!! They had proportions written down on each of the diamonds and every one had crown/pavilion angles listed as being in the neighborhood of 34-34.5 with pavilions of 40.7-40.9. Now ... I happen to be familiar with what those proportions should look like and everyone of em had rings of white under the table.

There was no way those stones were even the proportions they were stating. Of all the suppliers at the show Gary, and all those featuring H&A''s I think I only found 1 new source whose inventory was 50/50 (50% beauties vs 50% so so). I am an H&A advocate but as you state ... just because it''s H&A doesn''t necessarily mean it''s going to have superior brilliance.

RhinoKnight... We''re on the same page here. Generally if the proportions are those you listed and the H&A precision is top-notch the IS images that follow are pretty darn good.

RIGHT! Don''t show me a diamond ... tell me it has 34.5 crown angles, 40.7 pavilion angles, 56 table then show me an IS Images akin to this ....

 

[JohnQuixote]

Date: 11/23/2004 12:29:12 PM
Author: Rhino
RIGHT! Don't show me a diamond ... tell me it has 34.5 crown angles, 40.7 pavilion angles, 56 table then show me an IS Images akin to this ....

Preach it, brother.
Ideal Scope doesn't lie, and True Hearts & Arrows at those proportions don't lie either.

 

[Garry H (Cut Nut)]

These stones were not as bad as that one Rhino - more like the 2 on the top of this page http://www.ideal-scope.com/retail_buying_examples.asp - that whole parcel were mostly all H&A''s from a very big Canadian company / brand.

 

[valeria101]

Date: 11/23/2004 12:29:12 PM
Author: Rhino

...tell me it has 34.5 crown angles, 40.7 pavilion angles, 56 table then show me an IS Images akin to this ....

There are three diamonds showing nice arrows and less than perfect IS images on the_Solasfera_page on goodoldgold.com. Are the hart patterns of these guys by the book as well ?

 

[nicknomo]

Just curious, what is the cause of that particular leakage, if not from the proportions?

 

[valeria101]

Date: 11/23/2004 7:47:17 PM
Author: nicknomo
Just curious, what is the cause of that particular leakage, if not from the proportions?

Have you seen THIS

 

[JohnQuixote]

Val,

I don't think any of those IS images are poor, but I see the ones you indicate.

Before discussing the hearts patterning, note that all of those 10-cuts have at least one VG in symmetry and polish except for the 1.63 (which is Ex Ex). I think the 1.63 has the best IS image, and this would make sense if the meet point symmetry is "out" in some of the others. Considering the additional indexing and many more facets required for the cut I suspect it will be hard to find these with Ex Ex.

As for the hearts patterning, from a rigid point of view there is evidence of facet yaw/distortion in every pattern (if we're being picky). This could influence leakage, but is not exclusively a cause.

Jonathan has been working with these cuts closely (no doubt the lights have been flickering on his whole block as he puts them through his decathalon of tests)

and he may have further thoughts.

 

[noobie]

Date: 11/23/2004 7:58:17 PM
Author: JohnQuixote


Before discussing the hearts patterning, note that all of those 10-cuts have at least one VG in symmetry and polish except for the 1.63 (which is Ex Ex). I think the 1.63 has the best IS image, and this would make sense if the meet point symmetry is ''out'' in some of the others. Considering the additional indexing and many more facets required for the cut I suspect it will be hard to find these with Ex Ex.

Thanks John, I was wondering why more Solasfera stones were not Ex Ex