Are hearts & arrow cuts always ideals?

[eks6426]

If a diamond is a hearts & arrow cut diamond is it also then always an ideal cut or are there hearts & arrow patterned diamonds but with mediocre cuts?

 

[Regular Guy]

I could be wrong...but if the idea of "ideal" is pretty highly correlated with (maybe identical with?) efficient light performance...I believe recently Garry reported a good number of leakers.

Maybe he or others will help review this in more detail.

 

[WinkHPD]

We actually discussed this just the other day in this thread:

https://www.pricescope.com/community/threads/photographic-proof-ags-not-equal-to-h-a.25424/

We started out on the fact that not all AGS 0 cuts were Hearts and Arrows.

To answer your question more directly, I once had a perfect hearts and arrows picture in a stone (working from memory here, I may be off a notch, but not much) that had a 61 table and I believe a 62 or 3 depth. It was not even CLOSE to an ideal. I think I got it on my second trip to Antwerp many years ago, it did not last long, it was a beauty.

Wink

 

[Lord Summerisle]

I think you''ve got to remember h&a patterning is a seperate item to proportions in some respect. Ideal cuts refer to the proportions being within a set range... hence the square shown in the HCA graph - showing the 4 extremes in proportions for an ideal grade. (based around the mesurments of Towhowever-you-pronounce-it)

the H&A pattern if formed thought reflections of light internally. this is seperate to the proportions... it could be cut way outside the ideal proportions - but be well cut so as to reflect the light correctly so as to display the patterning.

thats is...

you can have a beautiful cut graded 0 by AGS that doesnt show a perfect hearts pattern... (say a lower girdle facet has been polished in a way which has Yawed the facet so as to cheat and get a Ex symetry grade (ie meet point)- but it screws the hearts as one half of a heart will be off)

you can have a diamond cut so as to have perfect internal symetry - but have crap proportions (say 33° crown and 42° pav)

or you can have both ideal proportions and perfect internal symetry and you end up with an ideal cut H&A.

Most of those we tend to talk about on here come from companies who trade on ideal cuts... which display H&A and recut those that fall outside that range or shops which select from inventories those which tick both ideal and H&A boxes and reject those poor performers. which is how we consumers can make the mistake of believing that it being H&A and therefore ideal - its just we have it quite good round here

of course this could all be hookum.. and im talking rot.
seek someone who knows.

 

[Garry H (Cut Nut)]

Yes Wink - there are plenty of really nice looking H&A''s patterns that can be right dogs.
This model has perfect Sir John patterns and 58% table / 61.9% depth.

 

[WinkHPD]

Hey Gary,

Does that stone have as little contrast as shown in the picture? Is it then a fairly lifeless stone, or is it pretty?

Wink

 

[Garry H (Cut Nut)]

It is a Daimcalc model 41 pavilion 35.5Crown and 58% table Wink.
And yes if you had one in your hand it would not impress you.
The Firescope would show the stone as having better dark stars than the ideal-scope because the lens hole is larger.

 

[JohnQuixote]

Date: 2/26/2005 1

1:10 PM
Author: Garry H (Cut Nut)
Yes Wink - there are plenty of really nice looking H&A''s patterns that can be right dogs.

This model has perfect Sir John patterns and 58% table / 61.9% depth.

Sir John patterns. You mean like waking up, putting coffee on, feeding the cats then checking email...?