.5 HCA - too low?

[Beacon]

I spotted a nice stone for my 3 stone project. Ran it through HCA and got .5 TIC range. All excellents on HCA and on the GIA cert.

Specs: 56 table, 34 crown angle, 40.6 pav angle, 60.1 total depth.

It meets all my specs, but I am concerned about the HCA.

I read that low HCA is not so good. My other stones in the project are 1.3-2.1 HCA scorers. Will this .5 HCA look bad - has anyone seen a stone like this??

Any info would be very much appreciated!

 

[DiamondExpert]

Only YOUR eyes can answer the question...

 

[Garry H (Cut Nut)]

if everything else is OK the only loss you will experiance is if you have a big head and you look at the stone from closer than 8 inches. Unless it is painted. Then shallow ish can be bad.

 

[Mara]

i don't know that i'd personally pair a slightly shallowish stone with 2 others that are not shallowish (one one a little deep?) in a 3 stone. especially if you are taking the time to piecemeal it out to begin with...aka putting lots of care into finding the right stones for the ring. keep looking until you find the ones you really want. i would probably only create a 3 stone from stones that were all pretty similar in terms of specs. just that anal part of me but it would bother me if i saw any sort of difference in 'look' between one of the stones vs the others kind of thing. and since i'd be scrutinizing the stones daily....i'd see a difference if there was one, especially with them all set side by side.

 

[Beacon]

That''s a good point Mara, it might be too shallow compared to the others and that might look strange.

There is a part of me that enjoys differences in things, but maybe that would be visually off putting.

I''ll seach on....

 

[Paul-Antwerp]

Nothing needs to be wrong with a very low (thus very high) HCA-score. One just needs to check a few more details, to make sure that the stone is cut very symmetrically.

However, Mara does have a point, that in a 3-stone ring, three similarly cut stones would probably match better.

Live long,

 

[MINE!!]

Date: 9/26/2006 8:31:36 PM
Author: Garry H (Cut Nut)
if everything else is OK the only loss you will experiance is if you have a big head and you look at the stone from closer than 8 inches. Unless it is painted. Then shallow ish can be bad.

OLOL... I just got that... Takes me a while..

 

[Mara]

i agree that sometimes differences are fun but for me with a 3 stone ring i''d probably not play roulette. esp if i was building it from scratch and taking the time to put it together.

did you see that 3 stone ring that we looked at when we were at Lane''s in SF? it was an old style 3 stone .... i think that the stones were I K and L. anyway the three of us looking at it could tell which was the L each time. it was obviously more yellow. and we could pick out the I as whiter. now these were old euro cut stones so they showed more body color by nature but that would bug me in a 3 stone ring. i would want the stones to have similar cut characteristics, and similar color if the stones were large enough to show body. clarity wouldn''t bother me as much as long as all three stones were eye-clean. but when you set 3 stones so closely to each other, your eye is bound to pick up small nuances in one vs the other.

unfort the only way to really know if a .5 would look different to you than a 2.1 is to see them in person. can you order them all in and see them side by side? you may not really see a difference. or you may!

 

[Regular Guy]

Date: 9/27/2006 10:14:22 AM
Author: MINE!!

Date: 9/26/2006 8:31:36 PM
Author: Garry H (Cut Nut)
if everything else is OK the only loss you will experiance is if you have a big head and you look at the stone from closer than 8 inches. Unless it is painted. Then shallow ish can be bad.

OLOL... I just got that... Takes me a while..

O, I don''t get it. I guess it takes me really long!

I don''t know why the low numbers point to the likelihood that you''d have big head blockage problems.
I don''t know why, for multiple stones sharing a low number, they would be regarded as " three similarly cut stones."
I do intuit why they''d be regarded as both very low and very high, but don''t really know why, except for the basis of recognizing stated preferences, that this would be a controversial finding.

I don''t get it, and unless I get some calculation that explains this, I want every dime of my money back from my Pricescope membership!

 

[Garry H (Cut Nut)]

Date: 9/27/2006 3:27:25 PM
Author: Regular Guy

O, I don''t get it. I guess it takes me really long!

I don''t know why the low numbers point to the likelihood that you''d have big head blockage problems.

I don''t get it, and unless I get some calculation that explains this, I want every dime of my money back from my Pricescope membership!

I know you know this stuff Ira, if you did not then your membership will be revoked with no refund

http://diamonds.pricescope.com/ideal.asp

 

[Regular Guy]

Date: 9/26/2006 8:31:36 PM
Author: Garry H (Cut Nut)
if everything else is OK the only loss you will experiance is if you have a big head and you look at the stone from closer than 8 inches. Unless it is painted. Then shallow ish can be bad.

Shallow and big head a problem, OK
Low number = shallow, frequently, why?

 

[Garry H (Cut Nut)]

there is enough written about it on that link and also at www.diamond-cut.com.au for a smart guy like you to understand it Ira

 

[WinkHPD]

Date: 9/27/2006 10:14:22 AM
Author: MINE!!

Date: 9/26/2006 8:31:36 PM
Author: Garry H (Cut Nut)
if everything else is OK the only loss you will experiance is if you have a big head and you look at the stone from closer than 8 inches. Unless it is painted. Then shallow ish can be bad.

OLOL... I just got that... Takes me a while..

I am not sure that you did. Gary was speaking the gemological truth. The obscuration pattern for a smaller head will be about 30 degrees of obscuration while a large headed person or a lady with a large hairdo may have a 40 degree obscuration and at closer than 8 inches the obscuration can be huge, causing the shallow stone to not perform as well as it would at a normal viewing distance.

The middle stone has a huge difference in the appearance of the stone from 30 degrees of obscuration from the 40 degree obscuration. I believe that it is a slightly shallow stone, obviously not one that would get a .5 HCA score, but it gives you the idea of how the size of the head and hair actually affects the appearance of the stone.

Wink

 

[Beacon]

This is an interesting chart. Does the #2 stone have 80% lowers? Looks like 75s. Or is that the effect of the small table on stone 2 compared to (for example) saone 3? I like 80% lowers and am getting all the stones on my 3 stone with them.

Where does this chart come from? Is it one that I can read on one of the PS tutorials?

 

[Regular Guy]

I hope I won''t bury a good idea here, with requests for some help.

It may be useful to many of us thicker ones to give some simple descriptors to terms used all the time.

For example:

a) shallow, or
b) steep/deep

My idea...they could be described any old way, and labeled in the glossary, here.

Presumably, this is also described visually here, in the HCA set of descriptions Garry''s also pointed to, but using other language to say the same thing could only help many of us.

Likewise, Wink, I wonder if you would like to share some text, describing the differences you see represented with your graphic, telling how you see # 1 varies from #5.

Date: 9/28/2006 12:46:15 PM
Author: Wink

I am not sure that you did. Gary was speaking the gemological truth. The obscuration pattern for a smaller head will be about 30 degrees of obscuration while a large headed person or a lady with a large hairdo may have a 40 degree obscuration and at closer than 8 inches the obscuration can be huge, causing the shallow stone to not perform as well as it would at a normal viewing distance.

The middle stone has a huge difference in the appearance of the stone from 30 degrees of obscuration from the 40 degree obscuration. I believe that it is a slightly shallow stone, obviously not one that would get a .5 HCA score, but it gives you the idea of how the size of the head and hair actually affects the appearance of the stone.

I doubt there''s any particularity to application that''s really meaningful, apart from differentiating perhaps, as in the HCA chart again, pendant vs e-ring. Nevertheless...one could always try this sort of ad:

Your jeweler who cares if your prospective fiance is a skin head vs a bouffant type of girl...because you should care...too!

 

[Garry H (Cut Nut)]

Date: 9/28/2006 12:46:15 PM
Author: Wink

I am not sure that you did. Gary was speaking the gemological truth. The obscuration pattern for a smaller head will be about 30 degrees of obscuration while a large headed person or a lady with a large hairdo may have a 40 degree obscuration and at closer than 8 inches the obscuration can be huge, causing the shallow stone to not perform as well as it would at a normal viewing distance.

The middle stone has a huge difference in the appearance of the stone from 30 degrees of obscuration from the 40 degree obscuration. I believe that it is a slightly shallow stone, obviously not one that would get a .5 HCA score, but it gives you the idea of how the size of the head and hair actually affects the appearance of the stone.

Wink

Wink I do not think it is fair to put the fear of God into people over such a stone.

Here is a model of this stone proportions given above with 40 degree blue in ASET.
It is a lovely stone and scpres very high on DiamCalc.

To reference the center stone in your chart - you should have given out the proportins - which I am sure are very much shallower than this stone.

 

[Garry H (Cut Nut)]

oops - mistake in the depth reduction - this is the correct ASET40 image.
Note too the free 3% extra spread / less weight!!!

 

[WinkHPD]

Date: 9/28/2006 1:03:16 PM
Author: Beacon
This is an interesting chart. Does the #2 stone have 80% lowers? Looks like 75s. Or is that the effect of the small table on stone 2 compared to (for example) saone 3? I like 80% lowers and am getting all the stones on my 3 stone with them.


Where does this chart come from? Is it one that I can read on one of the PS tutorials?

It was one of the slides from the AGS presentation at the JCK show in Vegas last June. AGS handed out CD''s of their presentation and gave us permission to use them. They are VERY useful in trying to demonstrate difficult concepts. I do not know the particulars of each stone, but the visual of the difference between 30 blue and 40 blue can be striking!

Wink

 

[WinkHPD]

Date: 9/28/2006 9:04:50 PM
Author: Garry H (Cut Nut)


Wink I do not think it is fair to put the fear of God into people over such a stone.


Here is a model of this stone proportions given above with 40 degree blue in ASET.

It is a lovely stone and scpres very high on DiamCalc.


To reference the center stone in your chart - you should have given out the proportins - which I am sure are very much shallower than this stone.

Gary, I specifically stated that the stone shown would definitely NOT have qualitfied for an HCA grade of 0.5. I have many stones in the 0.5 - 1.0 range and I think they are killer great looking stones, so I definitely do NOT want to put the fear of God into anyone over owning one of them. Personally I like them very much.

Wink

 

[WinkHPD]

Date: 9/28/2006 8:42:26 PM
Author: Regular Guy


Likewise, Wink, I wonder if you would like to share some text, describing the differences you see represented with your graphic, telling how you see # 1 varies from #5.

LOL! Not in this lifetime, there are not enough hours in the day to get into a discussion over the minutea with you. I am supposed to get a major part of my new web site to start filling with data tomorrow, so I am going to go to bed and sleep, it is going to be a long two or three weeks with little time for fun and games... I am so tired I am not even going to look up how to correctly spell minutia, I am pretty sure I spelled it wrong at least once.

 

[Garry H (Cut Nut)]

its late Wink - off to bed with you