Can a H&A Diamond have a 1.9 HCA score?

[sac75578]

As I understand it, a H&A diamond is suppose to be a better than an Ideal cut diamond. If that''s the case, can a H&A diamond have a HCA Score of 1.9, while a non-H&A diamond with a step below Ideal labeled as "Premium" have a HCA score of 0.9.

What HCA scores do H&A diamonds usually get?

Thanks.

 

[John P]

Date: 10/9/2008 12:18:52 PM
Author:sac75578
As I understand it, a H&A diamond is suppose to be a better than an Ideal cut diamond. If that's the case, can a H&A diamond have a HCA Score of 1.9, while a non-H&A diamond with a step below Ideal labeled as 'Premium' have a HCA score of 0.9.

What HCA scores do H&A diamonds usually get?

Thanks.

"Hearts & Arrows" refers to the precision of cutting required in the physical shaping of the stone, but is completely separate from the overall geometry that determines light performance.

The HCA result is based on the broad geometry of the stone. This is independent from whether a diamond was cut with enough physical uniformity to display H&A... So, in short, a "H&A" diamond could receive any HCA score.

By the way, 1.9 is as good an HCA result as 0.5 or 1.0. Once you are under 2.0 all results are equivalent.

Here is a thread with more info about H&A, if you're interested:
https://www.pricescope.com/community/threads/what-is-the-importance-history-of-hearts-and-arrows.68554/

 

[Lorelei]

Nice post Sir!

 

[neatfreak]

An HCA of 1.9 is a fine score. Lower doesn''t equal better once it''s under 2.

 

[chrono]

The HCA is just a tool to eliminate dud diamonds. As said above, a 0.5 HCA isn''t any better or worse than a 1.9 HCA. Once you have the score, then the rest depends upon your eyes (or ASET, IS, etc if you prefer). Also, H&A is a diamond cutting style. Some H&As are going to be gorgeous and some aren''t.

 

[Lorelei]

Date: 10/9/2008 1:09:54 PM
Author: Chrono
The HCA is just a tool to eliminate dud diamonds. As said above, a 0.5 HCA isn't any better or worse than a 1.9 HCA. Once you have the score, then the rest depends upon your eyes (or ASET, IS, etc if you prefer). Also, H&A is a diamond cutting style. Some H&As are going to be gorgeous and some aren't.

Actually if you mean diamonds which score over 2 or that the HCA ' rejects' are duds, not all are by any means - for the people who are reading and may not be familiar with how the HCA works.

Also Sac, don't go by labels such as Ideal Cut, Premium Cut etc which are often used by vendors, they are no guarantee of a well cut diamond. Evaluate each stone on its own proportions and desirable visual properties.

 

[kcoursolle]

Yup...and it can even have a score above 2. John summed this up nicely. HCA is best used as a weed out tool rather than a selection tool. Weed out stones with a higher score than 2 and then use OTHER selection criteria from there. A stone with a .9 HCA score isn''t necessarily better or worse than a 1.9.

 

[Rhino]

I would also add that there are H&A diamonds that do score over 2.0 on the HCA that have light performance on par with or better than diamonds that score under a 2.0!

 

[Regular Guy]

Date: 10/9/2008 9:10:14 PM
Author: Rhino
I would also add that there are H&A diamonds that do score over 2.0 on the HCA that have light performance on par with or better than diamonds that score under a 2.0!

Jonathan,

Garry allows for the same, but I''m less willing to throw out the baby with the bathwater.

How about a 5 on the HCA?

How about a 3.5?

Do you think there is any continuity to perception in the HCA system so that it provides some value added assistance to shoppers?

 

[Garry H (Cut Nut)]

There are good and bad H&A''s proportions too

H&A''s refers to a pattern that often has very good performance

 

[strmrdr]

Date: 10/9/2008 11:59:26 PM
Author: Regular Guy

Date: 10/9/2008 9:10:14 PM

Author: Rhino

I would also add that there are H&A diamonds that do score over 2.0 on the HCA that have light performance on par with or better than diamonds that score under a 2.0!

Jonathan,


Garry allows for the same, but I''m less willing to throw out the baby with the bathwater.


How about a 5 on the HCA?


How about a 3.5?


Do you think there is any continuity to perception in the HCA system so that it provides some value added assistance to shoppers?

I use the HCA to help decide if a diamond that I don''t have an IS or ASET image for is worth calling in to get one.
If I have an IS or ASET image then the HCA score is irrelevant as the IS/ASET gives a more accurate picture of the diamonds performance.

 

[Rhino]

Date: 10/9/2008 11:59:26 PM
Author: Regular Guy

Date: 10/9/2008 9:10:14 PM
Author: Rhino
I would also add that there are H&A diamonds that do score over 2.0 on the HCA that have light performance on par with or better than diamonds that score under a 2.0!

Jonathan,

Garry allows for the same, but I''m less willing to throw out the baby with the bathwater.

How about a 5 on the HCA?

How about a 3.5?

Do you think there is any continuity to perception in the HCA system so that it provides some value added assistance to shoppers?

Hi Ira,

Just to let ya know where I''m coming from.

Garry is correct in what he''s saying above and we really are in agreement for the most part. To the HCA''s credit too, in most instances many of the commonly cut diamonds that take hits do have notable leakage. Not too long ago we had a round sent in that was a 34.5/41.0 combo GIA Ex/Ex/Ex non H&A that had AGS 3 light performance (due to leakage) and IMPO rightfully deserved a hit. At the same time I have 34.5/41.0 combos (and have also seen 41.1 combos) that are perfectly fine and with no notable leakage when Optical Symmetry is precise. Precise Optical Symmetry does improve and increase light performance in diamond and there are instances the HCA is not taking this into account.

At times it is frustrating in the sense that there are people who perhaps already suffer from some form of analysis paralysis and we''ve seen folks walk away from diamonds exhibiting rare light performance, precision cut diamonds because of an HCA score that was unjustly knocking a perfectly beautiful diamond (even in a real critical examination).

These are not the norm but like any other technology there will always be exceptions to the rule and generally these are stones at or just over the 2.0 zone. Otherwise truly my hat is off to Garry for making such a tool accessible to the public. Like any tool one is going to utilize in any kind of diamond assessment it is important to understand its limitations as well as its strengths and is why I have written my own article on the subject.

Peace,

 

[sac75578]

Do these H&A pictures have good symmetry and porportions?

http://www.filesavr.com/1a
http://www.filesavr.com/2a
http://www.filesavr.com/3a
http://www.filesavr.com/4a
http://www.filesavr.com/5a

Here''s the GIA report
Round Brilliant
Measurements: 7.11 - 7.16 x 4.44 mm
Carat Weight: 1.38
Color Grade: G
Clarity Grade: VVS1
Cut Grade: Excellent
Proportions:
Depth: 62.2 %
Table: 55 %
Crown Angle: 34.5°
Crown Height: 15.5 %
Pavilion Angle: 41°
Pavilion Depth: 43.5 %
Star length: 55 %
Lower Half: 75 %
Girdle: Thin to Medium, Faceted
Culet: None

Finish:
Polish: Excellent
Symmetry: Excellent
Fluorescence: None

Thanks

 

[Lorelei]

Who is selling this diamond?

 

[sac75578]

idjewelery

 

[Garry H (Cut Nut)]

Date: 10/11/2008 6:22:24 AM
Author: sac75578

Do these H&A pictures have good symmetry and porportions?

http://www.filesavr.com/1a
http://www.filesavr.com/2a
http://www.filesavr.com/3a
http://www.filesavr.com/4a
http://www.filesavr.com/5a


Here''s the GIA report

Round Brilliant
Measurements: 7.11 - 7.16 x 4.44 mm
Carat Weight: 1.38
Color Grade: G
Clarity Grade: VVS1
Cut Grade: Excellent

Proportions:
Depth: 62.2 %
Table: 55 %
Crown Angle: 34.5°
Crown Height: 15.5 %
Pavilion Angle: 41°
Pavilion Depth: 43.5 %
Star length: 55 %
Lower Half: 75 %
Girdle: Thin to Medium, Faceted
Culet: None

Finish:
Polish: Excellent
Symmetry: Excellent
Fluorescence: None

Thanks

It could be acceptable to many as an H&A''s but it is an example of one that is too deep / steep for my taste