Ideal Cut?

[angel03]

http://www.whiteflash.com/round_ideal_cut/Round-Ideal-Cut-cut-diamond-556681.htm#

can someone explain why this is considered ideal cut? Check out the scope image.

 

[Iceman]

?

 

[Maxine]

Can someone share why the skinny arrows? I''ve seen that before , too....what cut combo causes that?????

 

[Cath]

Date: 2/10/2005 5:51:59 PM
Author:angel03
http://www.whiteflash.com/round_ideal_cut/Round-Ideal-Cut-cut-diamond-556681.htm#

can someone explain why this is considered ideal cut? Check out the scope image.

Not all ideal cuts are hearts & arrows, so I''m not sure why you''re pointing to the scope image?

 

[Maxine]

Please explain......lots of non-branded H&A stones do exhibit arrows.....what makes these arrows so skinny?

 

[valeria101]

The combination of table & crown angle & pavilion angle fall just so... And the Ideal Scope is bright red allright

So... it''s not H&A, but "ideal" does not mean "H&A". AGS0 Ideals has never been meant to indicate Harts and Arrows diamonds althought the word "Ideal" is used. Same for the other cut grading systems based on numbers. The stats alone can predict light return reasonably well, but the H&A pattern is too precise a thing to survive measurement error and averaging out.

As far as I know, at least.

 

[angel03]

So, the absence of Hearts and Arrows doesn''t necessarily affect the beauty of a stone?

How about this one:

http://www.whiteflash.com/round/Round-cut-diamond-556684.htm#

 

[Lord Summerisle]

Well first of all... i think this is a mute point about it being a H&A - since its in the expert selection... which means it didnt meet WFs standard of H&A. but its been shown that many ''ideals'' can show arrows.. but... going off the presented data... it isnt a AGS0 on the cut... the 33.6° crown puts it in the AGS1 section... the accompanying sarin report i think confirms this with its ''proportion grade 1'' but then its a very close thing... with the Sarin''s measurements ranging 33.2°-34.1°

Im guessing at the reson for the thin arros shafts being that the length of the lower girdle facets being a lot longer than normal.. causing very thin pavilion facets... of which the arrows are the reflections of. and hte long thin arrow heads from a slightly high crown, coupled with low crown angle, results in a long elongated kite facet (the main crown facet)...

i would guess given the known tolerances that put in the sarin machine again... it might come out with a result of 33.7° for the crown.. which would put it back in the AGS0 camp...

i suppose its an illustration of a good reson for the reclassification of the cut grades...

the second one.... well that aint put forward as a ideal... (i think it comes out a AGS2 grade) and i think it falls right off the scale for performance...its fallen over the edge of the cliff into the deep blue. plus it aint eye clean... great big inclusion about 3:30 on the ideal scope.

how it would look in person i dunno...

umm hope some of that makes sense (i hope also that im right - otherwise i''ll feel a right t**.. actually on that note... Im coming honey!)

 

[Maxine]

What are you looking for???? Of the two you picked, the first definitely looks better.....Are you looking at size, price.....??? Have you read any of the tutorials here or on any other websites re: diamond education?? You could always call a vendor and ask for an explanation of the pictures you are seeing......(the second one did not state ideal cut...).

 

[Rhino]

Date: 2/10/2005 5:51:59 PM
Author:angel03
http://www.whiteflash.com/round_ideal_cut/Round-Ideal-Cut-cut-diamond-556681.htm#

can someone explain why this is considered ideal cut? Check out the scope image.

Greetings Angel,

I''ve been asked to comment from another forum member on the questions raised in this thread. I try not to comment on diamonds where the seller is revealed becuase I don''t want my comments or criticisms to be miscontrued as any kind of *attack* however I really don''t have anything bad to say ... just the facts.

Definitely an interesting looking subject. Under the current grading system this diamond would not be considered ideal due to the average crown angles falling at 33.6 degrees. The listing of it as an ideal by WF must be a typo and knowing my friends there I am positive that''s the case.

That answers your question directly. It''s not considered ideal.

Some other points to note however. Now ... while that diamond is not considered ideal under the current grading standards (and quite possibly even under the new one about to be revealed), the combination of angles on the major facets & minor facets will produce a diamond that will have excellent scintillation but will do so at the expense of broader flashes of fire in direct light conditions and contrast in diffuse light conditions (lack of darks which add contrast, primarilly from the arrows).

The reason I say it may not get "ideal" according to the new cut grading system that''s coming out is because the lower girdle facets appear to be cut *too long* which causes the extremely skinny arrows.

My advice to you Angela... if you are intrigued by this diamond it would not hurt to order it and *see it*. I would also advise to compare it to another diamond with comparable proportions but different minor facet cutting to see which you prefer. I know people who prefer the look of this particular type and considering most of the garbage being offered on the market you could certainly do much worse. I wouldn''t disqualify it unless you can see it and compare. My personal preference is not for this kind of stone but yours may well be.

 

[Rhino]

Good question Maxine. The arrows are so skinny because the facets between them (the lower girdles) have been pulled down or cut very long. The lower girdles are those between the pavilion mains and *dictate* their thickness ultimately affecting the diamonds appearnace. It is my personal conviction that lower girdle cutting impacts the appearance of the diamond as much if not more (in some circumstances) than the main facets. Before we proceed to answer this, these are the lower girdles (pictured below and colored).

 

[Rhino]

Here is a simulated IS image of an ideal cut diamond with 80% lower girdle depth (or about 77% lower girdle length for you Sarin users).

Note the thickness of the arrows. In direct light conditions, these, along with the lower girdles are going to kick back some serious fire which will be typified by bold broad flashes of light. There are other reflective areas in the diamond in this example which will also kick back some hella nice scintillation in direct light as well, not to mention superior contrast in diffuse light conditions.

 

[Rhino]

Here are the results when you pull those lower girdles down to 90% (similar to diamond in question).

It drastically alters the appearance. As I''ve said you may prefer this or you may not. The only way would be to see and compare. Looking at the GIA would also disqualify this from being ideal as well since the polish/symmetry are not ex.

Hope this helps.

Kind regards,

 

[brandanop]

"So, the absence of Hearts and Arrows doesn''t necessarily affect the beauty of a stone?

How about this one:

http://www.whiteflash.com/round/Round-cut-diamond-556684.htm#"

YIKES! Isn''t that a Fisheye? I am seriously considering Whiteflash. If that is a fisheye, and it is an expert selection, I am scared.

Pete

 

[valeria101]

Thanks Jonathan

There are non H&A and non AGS0 in the WF expert selection. This is the first time I hear about them around here !

I must say I didn't ask, but they seem to be selected for the same Ideal Scope criteria as fancies would be (lack of lickeage and sufficient contrast) and size/weight. If WF has some fixed range of numbers for these, it is not cited on their website.

Perhaps John could chime in as well.

Anyway, either of the two stones does something well: the first has both near (conventional) idea proportions and near-ideal price, the second appears to be a brilliant piece with very good spread. By numbers or photos it is nowhere close to fish eye (link to fish example).



Beauty and H&A ? No idea. I know what's beautiful to me. It is quite a different business to determine what looks beautiful to everyone else. It's nice to have some choice.

For what that matters for the H&A follwing, the oposing camp appears quite strong. It came as a bit of a surprise that not more cut grading standards went for H&A or at least the related tools and conceps ( = using some standard viewer and grading against a standard pattern - much as I understand). AGS and GIA decided that this pattern is not critical for diamonds' good looks and they do not grade it, despite serious effort applied to pin down tollerances for cut parameters. It would have been easier for them, I think, to just embrace the H&A concept and grade the cut of round brilliants after H&A rules. Let's say these guys are all too conservative and need to catter for too many practical issues as well (as in not calling almost all diamonds on the market bad names out of the blue). However... it does feal strange to call all that effort wrong. Perhaps the cutoff of the resulting parametric grades is too loose for for some, and some limits of the applied models debatable, but the resoning behind it all appears hard to trash in one blow H&A or no H&A.

 

[JohnQuixote]

Greetings gemophiles.

I have been out of town for the last few days with remote access to PriceScope and no access to email. Thanks Val for alerting me to this.

The kindly Rhino has done a yeoman's job of explaining particulars here. On the original diamond in this thread I assume his explanation right - the 33.6 angle did not get classified correctly (?) I have a message in to HQ about it. The second one is not a fisheye. Rhino's additional illustrations are a good look at particulars of construction... He is a clever and handy mammal (thanks, bud!).

Two things about Expert Selection:

1. As good Lord Summersisle mentioned - No Expert Selection diamond is what we would call H&A. If you look through the ES rounds you can find a good number which were "A Cut Above" candidates that came close but did not quite pass our checklist. Of course, none of the diamonds in this thread come close to that - but we do not feature just ACA or near-ACA in Expert Selection - we span a broad range of selections and price points. Some people are not seeking H&A or definitive patterning, they are seeking a beautiful diamond at a good price.

2. If you look at the IdealScope images of each you will see why these are considered "Expert Selection." Each ES represents what we consider the best value for the money in its class and category and they are all beautiful. So, compare not only the particulars of construction like arrow shafts, etc. - but check the IS images and then compare all elements balanced with (ta-da!) the price.

Hope this helps. I'm back in town Sunday.

 

[Maxine]

Thanks for all of the input.........