Good HCA means H&A?

[layman]

I saw this diamond in a shop yesterday.
0.57 F VS1 AGS000
Table: 57%
Depth: 61.0
Crown Angle: 34.8%
Pavillion Angle 40.7%
Culet PT
Girdle: 0.9-1.7%

It gets 1.1 ex-ex-ex-vg on HCA

From the scope it looks like it has good H&A but I am not and expert.

1) The hearts does not touch arrow head.
2) The heart cleft seems to be shallow - < 8%
3) The arrows seems to be okay - not very sure

YOu see, the pattern changes even if I move my head slightly, so it is difficult be certain of the pattern I see.

I read BrianTheCutter''s page on whiteflash but I am still not sure if they are perfect H&A - obviously, my nick is layman.

Does it mean that if the HCA score is very good, the stone is likely to be perfect H&A?

I am thinking of getting it appraised but can appraisers certify H&A?

And the shop is quite low tech so all I get is a view into the H&A scope, no pictures, etc.

 

[Mara]

No...a good HCA score does not mean anything but it scores well on fire, brilliance, scintillation and spread.




There are plenty of great AGS0 HCA performers that are not even H&A...much less 'perfect H&A' which is harder to find.




Important to note that most well-cut stones will exhibit SOME PATTERN of Hearts and Arrows when viewed. The 'true' H&A is really what it's all about in terms of markup and/or the 'designation' of the name.




Since you don't have any images, hard to say really, but if it is not being billed as an H&A in the store, chances are it's really not. I say this because if you were a jeweler selling a stone, wouldn't you want to mark it up if it WAS H&A and/or at least talk about it? Chances are it's not..or if it is...the jeweler doesn't even know what he has. Which could be your benefit.




Brian posted some H&A images recently in a thread, and those are great examples. Also GOG's site has some great examples of H&A vs non....there are what some would call 'almost H&A' which mean that the stones exhibit a very nice pattern of hearts and arrows, but the arrows may be slightly sloppy at the ends, or the hearts may be slightly misshappen (look for slightly smaller hearts than the others...) and/or the clefts may be deep (there shouldn't be a deep cleft or cleft separation at all).




Chances are you have an almost H&A that looks very nice under the scope. If the price is right and the stone looks good to your eyes, the numbers are very nice..and the HCA corroborates. So it probably would be a great deal as an almost unbranded H&A.

 

[layman]

Well, it is going for US$2110.

Wonder if this is a good price to pay.

I there any appraiser out there who are qualified to certify H&A or non?

 

[Mara]

It sounds like a pretty good price to pay...found this as a comparison option for specs and price except fluor is Medium Blue:




http://www.whiteflash.com/diamonds/diamond_Details.aspx?itemcode=GIA-12649392#


.60 F VS1 AGS0 with 0.9EX on the HCA for $2050 *Pscope price




If this stone did not have med blue fluor it would maybe be a few hundred more since the trade discounts for fluor...so your $2110 sounds very nice for a stone like this with similar specs that does not have fluor.




As far as appraisers, send it to someone like Rich Sherwood, Rock Doc or Dave Atlas who will be able to tell you their thoughts on true H&A during the appraisal.

 

[tessa]

PS is such a wonderful resource for these kinds of questions.

You have come to the right place!

 

[mdx]

Hey Mara

Very nice reply. I do love the easy to understand help you give consumers,
Good Stuff

This is an interesting subject identifying “ true hearts and arrows”
Excluding inferior symmetry and poor cutting we group H&A’s into two groups.
Firstly those where the cutter intended to cut an Ideal H&A and and secondly where an Ideal cut displays H&A’s

Johan

 

[Mara]

Thanks Johan...

What an interesting way to group the H&A...intended and accidental.

 

[valeria101]

Not sure why is it necesary to hunt down harts or arrows....

I would try to summarize my take on this (simmilar, I hope, to the above said on this thread) that:

All H&A get high HCA scores, but the reverse is not true.

Diamonds with high HCA need to have the right minor facet proportions and comply with the assumptions of the HCA (thin-medium girdle and superior symmetry) to display the H&A pattern.

As a side effect, stones cut to become H&A, would get high HCA scores, even if the H&A pattern is not perfect to the n'th degree (as your stone seems to be the case). These diamonds would most likely comply with the required parameters for minor facet proportions and symmetry to allow the HCA system to accurately predict optical performance.

Hope this makes sense...

 

[layman]

valeria101, what you have said definitely make sense.

But I believe there are H&A out there that do not fare very well on HCA. Think I read it here, from one of Mara's reply:

https://www.pricescope.com/community/threads/validity-of-hca.3211/

I always have this impression that AGS000 is the top few percent of all diamonds -> H&A is the top few percent of AGS000 and High HCA is the top few percent of H&A.

So to get H&A with high HCA, you get the best of the best of the best.

But I guess, from the replies to my question, since there are H&A which have low HCA and high HCA which are not H&A - things are quite different from my understanding.

So, if it is possible to get low HCA for H&A and high HCA with imperfect H&A, then which one is more important and would likely make a beautiful dimaond?

Maybe Garry a.k.a CutNut, the inventor of HCA and one of the most respected H&A cutter, BrainTheCutter, would like to comment on this.

 

[Mara]

In terms of what you noted in the top % and how you think about it...this is the way I see it.




There are many diamonds out there. Only some will be AGS0 (Ideal Symmetry, Polish and Cut Parameters). Not all AGS0 stones perform well on the HCA. I have run some through that come up with 4.2 scoring or similar! So AGS0 does not automatically equal well-cut stone.




But if you start with an AGS0 stone, great. Because from there, run the #'s through the HCA. Score under 2.0? Great. Now you are getting somewhere. This stone is probably in the top 5% of all stones out there. Wait the IdealScope image shows little light leakage? Even better. Wait, it shows a great H&A pattern with not alot of variances, no deep clefts, no funky hearts etc? Excellent! NOW you have got a stone that is probably in the top 2-3% of all the stones out there.




So even if a stone does not display those perfect H&A...you are still in the top 5% with great numbers, AGS0 and great HCA score and a good IS image. Depends on how picky you want to be and even more importantly, how picky your budget allows you to be!!

 

[layman]

You are right, Mara besides a certain Mr Gates and his friends, most of us has a budget to keep to.




Which is precisely why I ask all these questions /idealbb/images/smilies/1.gif . If I can afford to buy anything I want, I'll just buy the best H&A with high HCA no matter what it costs. /idealbb/images/smilies/3.gif No problems.




From the postings above, I come to understand that you can have high HCA without H&A and vice versa.




If if my budget allows me either to have high HCA or H&A with low HCA, which one shall I choose?




Now, Mr Holloway seems to feel that HCA is more impotrant




http://www.ideal-scope.com/symmetry.asp




"Light return is the bricks and mortar, hearts and arrows symmetry is just a coat of paint."





I believe other people, like perhaps yourself, will have other views that H&A is the key factor to a beautiful diamond.




As a consumer, I just want to have an idea of what can I compromise without much lost in quality. Just like if I go from D IF to F VS2, I know I still get almost comparable quality but saves a lot of money.




So if I get good HCA and non-ideal H&A, do I get the same effect. Minor degradation of quality with major decrease in price?




Or is it the other way round? I settle with an H&A with mediocre HCA score?




I know, HCA does not affect pricing a this moment. But a high HCA stone might not be available in the carat that you want, so you may have to get bigger stone to get better HCA, so in a way it may affect price. No doubt indirectly and in a more complex way.

 

[Mara]

If I had to choose...I would choose non H&A with great HCA and great light return IdealScope image and great #'s.




H&A is like the icing on the cake I guess...maybe that is what Garry was noting in his quote there. There are beautiful stones out there that are NOT perfect H&A but when scoped may show the pattern. I am sure visually they perform just as well when all the other ducks are lined up in the row too.




So I wouldn't FOCUS necessarily on finding H&A, esp if you are looking for unbranded and do have a budget to stick to...I'd look for good numbers, good looking stone, good scope image and good HCA Score. I would be happy with that if budget did not allow the true H&A. and you may be surprised at the pattern it shows, if its not perfect but 90% there...thats still sweet!

 

[Rank Amateur]

Remember that the HCA does not guarantee top shelf performance for a great score. It helps you narrow things way way down, but in the end it is best to let your eyes choose.