ASET Test on a RB?

[tarator]

What does it show? And what are the disadvantages of not getting one if I have an ideal scope?

Tara

 

[Lorelei]

Date: 10/1/2009 3:31:41 AM
Author:tarator
What does it show? And what are the disadvantages of not getting one if I have an ideal scope?

Tara

Hi Tara!

ASET breaks down the light return of the diamond into colour codes, Idealscope basically shows light leakage although ASET can show leakage too as well as the light return. Personally I can normally get a pretty good idea from an Idealscope image for a round diamond ( for fancies though ASET is preferred) although it is nice if you can get both images for a round stone. This summarizes what ASET does from this link which you have probably seen.

[/url]is also a very useful link which explains ASET.

In general RED should be maximized. Some BLUE is necessary. Too much GREEN is undesirable. The distribution of the three colors is important. WHITE should be minimized.

Different Shapes have Different Standards

Each cut has its own set of light performance standards. Fancy cuts are not held to the same standards as Round Brilliants, which are the best at returning an abundance of RED direct light.

Round Brilliant Examples

High Performance (Rounds)

In high performance rounds RED is dominant, broken by an even BLUE contrast pattern. GREEN is present in small, symmetrical quantities. WHITE leakage should be minimized.

Brightness and Dispersion

Abundant RED indicates abundant light return, which most people find appealing. The balance of dispersion or “fire” seen will depend on the diamond’s configuration or “make.” Large tables and shallow crowns have more whiteness then fire. Small tables and high crowns have more fire than whiteness. Middle combinations are balanced.

Contrast

BLUE creates the contrast pattern in a round diamond. These areas are obscured by the observer in the face-up position. Tilt the diamond slightly and those areas erupt in light as others go dark. Tilt it more and they swap again. Keep tilting and the on-off sparkle you see is scintillation. In high performance diamonds the character of scintillation is influenced by the table and lower halves. Short lower halves result in fewer, broader flashes. Long lower halves create more numerous, smaller flashes. Middle combinations are balanced.

 

[Garry H (Cut Nut)]

If you have an Ideal-scope image or an idea-scope you do not need any ASET images for a round diamond

 

[Paul-Antwerp]

Garry,

I agree, but also disagree.

From the point of view of light leakage, and the stone returning light to your eyes, most rounds gather their light from the red area in the ASET, thus most rounds will show red in the ASET, where they show red in the Idealscope. In that sense, for most rounds, if one has an Idealscope, the ASET is predictible, and not really needed to confirm what one already knows.

However, I am quite sure that in limited cases, the ASET will show a decent amount of green that is red in the Idealscope, and for those cases, the ASET offers extra information. If such cases represent 5 or 10% of rounds, I do not know. Therefore, I would add a small caveat to your remark.

Furthermore, consumers vary in their desires. Some will want a decent above-average stone with a good Idealscope, others want the best of the best. In that sense, I think that for the latter group, the ASET will show more information, not only about the origins of light hitting your eye, but also about the stone''s optical symmetry.

Just trying to be complete.

Live long,

 

[Garry H (Cut Nut)]

Date: 10/1/2009 9:26:08 AM
Author: Paul-Antwerp
Garry,

I agree, but also disagree.

From the point of view of light leakage, and the stone returning light to your eyes, most rounds gather their light from the red area in the ASET, thus most rounds will show red in the ASET, where they show red in the Idealscope. In that sense, for most rounds, if one has an Idealscope, the ASET is predictible, and not really needed to confirm what one already knows.

However, I am quite sure that in limited cases, the ASET will show a decent amount of green that is red in the Idealscope, and for those cases, the ASET offers extra information. If such cases represent 5 or 10% of rounds, I do not know. Therefore, I would add a small caveat to your remark.

Furthermore, consumers vary in their desires. Some will want a decent above-average stone with a good Idealscope, others want the best of the best. In that sense, I think that for the latter group, the ASET will show more information, not only about the origins of light hitting your eye, but also about the stone''s optical symmetry.

Just trying to be complete.

Live long,

I appreciate your thoughts Paul - but 1 question and one comment

1. can you identify the proportions or show any examples to indicate what you mean?
2. The ideal-scope and ASET are both useful for rejection and in both cases in my opinion the results would be identical for experts and the ideal-scope would be much easier for non experts to use and understand.

 

[Paul-Antwerp]

1. No examples, Garry, as I am not busy in that area. What I am refering to is a theoretical possibility, not something that I encounter regularly. As such, I agreed with your statement, but found it too general.

2. If you look at both as a rejection-tool for potential brightness only, you have a point. But the sad reality is that both tools are used with broader aims in mind.

Live long,

 

[strmrdr]

Where I find ASET sometimes useful with a RB is if the Ideal-scope shows something is off.
The ASET with more information is easier to tell what is going on sometimes.
With rounds it is just as easy to say no and move on based on the IS so it isn''t a huge issue because there will be others out there in pretty much any range.

 

[tap02150]

This kind of goes along with storm, but what if the ideal scope was tilted? Something is not showing correctly on the ideal scope. Is this where an ASET may prove/correct the thoughts about the ideal scope? Almost like, a second opinion on a diamond lol. I could be wrong.

-ted

 

[Garry H (Cut Nut)]

Date: 10/1/2009 11:13:37 AM
Author: strmrdr
Where I find ASET sometimes useful with a RB is if the Ideal-scope shows something is off.
The ASET with more information is easier to tell what is going on sometimes.
With rounds it is just as easy to say no and move on based on the IS so it isn''t a huge issue because there will be others out there in pretty much any range.

Exactly Storm - you and a few others can get extra info but it is unrealistic to think that would change any buying decisions.

Paul i am trying to think of the exceptions you mentioned. nada - except maybe for deciding if the optical sym is bad, very bad or extremely bad.

The ASET is the most useful tool for assessing fancy shaped diamonds to be considered. Sergey uses it as a rejection tool - I generally am happy enough to use it as a selection tool for cut quality in fancies.