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Explanation for Asscher way outside of ideal cut range still appearing awesome?

Venzen007

Venzen007

Shiny_Rock
Joined
Dec 22, 2008
Messages
212
According to https://www.pricescope.com/wiki/diamonds/asscher-cut-diamond

...an asscher I'm considering is way out of ideal specs. That said, in side-by-side comparisons with several diamonds with specs that are more inline with these ideal specs, the one I'm considering clearly outperforms the others. This begs the question whether the above reported "ideal" specs are hard and fast or overly generalized. Anyone have any thoughts on that?


This particular asscher I'm looking at even has several areas in the ASET that show areas of light leakage, but again, in several, side-by-side comparison videos under various lighting, this particular stone seems to out perform the others. What's going on here?

I'm including the ASET and the measurements for any comments.

Table 61.3%
Crown 19.6%
Pavilion 45.7%
Total Depth 69.2%
Culet None
Girdle Thick
Ratio 1.00
Sym EX
Polish VG
sketch-1561688942023.png
 
So you have seen it in person? Pick the one your eyes love.
 
I think the ASET in the OP looks pretty reasonable, to my inexperienced eyes :)although there might be some P3 facet issues in the very centre.

Good amount of red and green (direct and indirect light return), intermixed with some interesting blue and black (obstruction / contrast).

Yes, a couple of areas of white (leakage) but don't forget it is a static, one-angle image. In real life, when it is constantly moving around, those areas of leakage face-on might be performing very nicely at tilt angles.

Check out the tilt-ASET images for Mildred to see what I mean about it changing as it moves!
https://www.pricescope.com/communit...-code-name-mildred.236249/page-6#post-4337522
 
Ultimately, there are no ideal stats for fancy cuts. There ARE recommended stats that are more likely to produce better performing fancy cuts, but they are not guaranteed.
You CANNOT judge a fancy cut diamond using stats. This is proof of why.
Fancy cuts vary...A LOT!
ASET, videos in various lighting environments, and at multiple angles, as well as naked eye examination are the real tools recommended to examine a fancy cut diamond. Fancies are tricky; step cuts even more so.

If you want a more classic Asscher, reach out to GemConcepts, @diagem
August Vintage, Inc., @Rhino
and Diamonds by Lauren. Good Old Gold carries some pretty impressive Asschers, as well.
If you want to check out the Octavia, GemConcepts, GOG & DbL (I believe) carry them.

If you’re looking for expert evaluation of this ASET, @Karl_K @Rhino and @diagem are your guys.

Adding:
Amazing article by @Karl_K to help you better understand why numbers aren’t everything in the world of step cuts.
https://www.pricescope.com/articles/performance-and-p3-facets-discussion-about-step-cut-diamonds
 
I suspect that the "ideal" specs that you refer to are for a square emerald cut. Not every asscher is a square emerald cut. I have a diamond with similar proportions to the one that you are considering. It is cut in a style to mimic a Royal Asscher.
Could you link a video so that we can view the diamond? Please share how many pavilion steps the diamond possesses.
Does the lab report refer to the diamond as a square emerald cut or another name?
 
Is there a topic on crown height and step cuts similar to the discussion of small table/high crown on some of the MRB diamond discussions. Could someone please explain the benefits of the crown facets and angles in light performance? It might help OP understand why this asscher performs so well.
 
@princessandthepear , the GIA report refers to it as a Square Emerald Cut. The size is 6.83 x 6.81 x 4.71. You'd asked about the pavilion cuts, here is the diagram from the GIA report. Tell you (or anyone else) anything? Screenshot_20190630-153845~2.png
 
princessandthepear said:
Is there a topic on crown height and step cuts similar to the discussion of small table/high crown on some of the MRB diamond discussions. Could someone please explain the benefits of the crown facets and angles in light performance? It might help OP understand why this asscher performs so well.
Click to expand...
I think crown height in asschers is similar to MRBs in terms of performance differences - higher crown (and smaller table) increases opportunities for dispersion of returned light into coloured fire :)

Yoram also talks about the '3D sculpture effect' in stones that are cut well, which I've not seen in person (because the stores round here are rubbish :( lol) but which I think I've seen in a couple of videos!

@Karl_K is, naturally, the go-to man for stepcuts - he might be able/willing to give more detail on crown impacts!
 
Asschers can have 3, 4 or even 5 step pavilions. The Royal Asscher(A branded cut) has a 5 step pavilion. Most square emerald cuts will have a 3 step pavilion. My diamond is not a square emerald cut but a cut cornered square step cut. It is cut deeper in the corners with a high, smaller crown, and in this case, a 5 row pavilion(RA clone). Its light performance is more akin to a round brilliant with lots of small, pastel squares of light and rarely do I see large, white broad flashes of light.
I believe that you have discovered a well cut square emerald whose complementary angles enable it to perform beautifully. Your eyes are the ultimate judge of performance and beauty in diamonds. If this diamond pleases you then either purchase it or place it on hold and post a video of it here to be critiqued if you are uncertain. Good luck in your search!
 
@OoohShiny thank you for commenting on the crown height and performance aspect. I have been following the discussions of small table/ high crown/ larger crown angle with great interest and wondering how this applied to step cuts. It is a shame that so many asschers are cut with shallow crowns currently. I would love to have one of Yoram's asschers or an Octavia one day but will have to enjoy them in the lovely videos or pictures from fellow PSers.
 
princessandthepear said:
@OoohShiny thank you for commenting on the crown height and performance aspect. I have been following the discussions of small table/ high crown/ larger crown angle with great interest and wondering how this applied to step cuts. It is a shame that so many asschers are cut with shallow crowns currently. I would love to have one of Yoram's asschers or an Octavia one day but will have to enjoy them in the lovely videos or pictures from fellow PSers.
Click to expand...
I think you can be more than happy with an RA clone until you get a Yoram stone! :D

Do you have a thread on it? I can't remember!
 
Venzen007 said:
@princessandthepear , the GIA report refers to it as a Square Emerald Cut. The size is 6.83 x 6.81 x 4.71. You'd asked about the pavilion cuts, here is the diagram from the GIA report. Tell you (or anyone else) anything? Screenshot_20190630-153845~2.png
Click to expand...

3 crown facets. 3 pavilion facets. The angles must work well for the ASET to be as good as it is.
 
@Karl_K , It sure seems to compared to the four others in the comparison video. I'll try to upload soon (on planes the rest of the day/evening), and I'll have it in-hand the middle of the week to personally take a look.
 
When the background of the ASET is white and there are areas of white in the ASET, what, then, do the black areas represent in that ASET? In the one I posted, I see red, green, blue, white AND black. ? @Karl_K
 
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I had forgotten what my antique asscher was called by GIA and it is a cut-cornered rectangular step cut. It has three steps.

I'll look forward to seeing pictures of this asscher. I also think it has potential!
 
Venzen007 said:
When the background of the ASET is white and there are areas of white in the ASET, what, then, do the black areas represent in that ASET? In the one I posted, I see red, green, blue, white AND black. ? @Karl_K
Click to expand...
hole in the center of the scope comes out as black.
Sometimes its an issue sometimes not.
This one the stone is to far into the scope or as sometimes happens someone enlarged the hole.
High crowned asschers are extremely picky about placement in ASET scopes where a RB has a very wide sweet spot where it gives optimal images.
The reason is that an RB draws light from narrow ranges.
 
Gotcha, so the black isn't leakage in this case, but a return of light from the area of the scope that is the hole, which is basically just an additional (with the blue) narrow range of light obstruction?

Would you say this is typically good, bad, or neutral for pendant set stones, or is there no way to know with the given information since it could be a product of the interaction of the high crown and ASET design?
 
Venzen007 said:
Gotcha, so the black isn't leakage in this case, but a return of light from the area of the scope that is the hole, which is basically just an additional (with the blue) narrow range of light obstruction?

yes

Would you say this is typically good, bad, or neutral for pendant set stones, or is there no way to know with the given information since it could be a product of the interaction of the high crown and ASET design?
Click to expand...
If its an issue or not depends on a lot of factors.
Less so in a pendant than a ring because of the viewing distance.
Then you have the cases where its a false negative which is not that uncommon in shapes other than RB.
ASET and for that matter the agsl grading system was designed for a mrb the use on another shape is simply not as good.
ASET was designed with assumptions of several factors based on a mrb and those assumptions are not universal.
 
First check this for a primer on virtual facets:
https://www.pricescope.com/articles/virtual-facets-and-patterns-discussion-about-step-cuts
Small table:
Notice the differences in the patterns of the virtual facets under the table and outside the table.
The table size changes the ratio of large to extra large virtual facets(under table) to medium/small sized virtual facets.
The different virtual facet sizes flash differently with the larger virtual facets flashing slower but more bold which is great but there needs to be a balance.

The high ch impacts the flash rate with the higher crown tending to show more life if everything else is aligned.
It dances a bit better in other words.
But better aligned facets can make a low ch stone dance better than a high ch stone.
 
Karl_K said:
The high ch impacts the flash rate with the higher crown tending to show more life if everything else is aligned.
It dances a bit better in other words.
But better aligned facets can make a low ch stone dance better than a high ch stone.
Click to expand...
Nothing is ever simple... :lol:
 
Karl_K said:
better aligned facets can make a low ch stone dance better than a high ch stone.
Click to expand...

@Karl_K , would you say a higher crown is cheating or a shortcut to better alligned facets or is it just a different way to achieve the same results? Any drawbacks to the higher crown just being a higher crown, other than apparent size to carat weight?
 
Venzen007 said:
@Karl_K , would you say a higher crown is cheating or a shortcut to better alligned facets or is it just a different way to achieve the same results? Any drawbacks to the higher crown just being a higher crown, other than apparent size to carat weight?
Click to expand...
This is getting into a problematic area because I designed the octavia above.
But I will try to keep it generic:
No matter how high the crown if the facets dont work well together its a dud.
The facets working together is fundamental and inescapable.
Once you have that then the other factors come into play.
A high crowned stone will more likely than not have much better spread than a low crown stone of similar or even much less depth.
Look at mm spread not depth.

I feel I would be pushing the rules going into it more.
 
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