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Need advice on H&A - Specs inside

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CSI_guy

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Hello all,

I have been lurking these forums for quite some time now and have learnt so much. I''m about to take the plunge and dive right into getting an H&A stone. Feedback for this diamond would be appreciated:-

Here are the details:

1.28 RB, H, VS2
Depth: 60.2, Table: 56, Crown angle: 34.9, Pavilion angle: 40.6, Girdle: Thn to med, No fluor. Cutlet is pointed. ID/ID for symm and polish.

My question: Since this stone scores 0.6 on the HCA does it mean that a score of 1.0 would have been more appropriate for this carat size?

H&A pic: (See attachment) (H&A''s are good as is light return)

HA01.JPG
 

belle

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that is not at all what the hca score means. hca is a tool for rejecting poor performing diamonds. scores under 2 mean you have eliminated the chances of getting something less than ideal. there is not a ''better'' diamond once you get under 2.
2.gif
 

strmrdr

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That combo would make a better pendant than a ring.
It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light.
On the good side of the coin it would probably tolerate dirt buildup better than some.
 

CSI_guy

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Thanks for the input belle and strmdr.

I understand the concept of anything under 2 on the HCA being great.

My question was more along the lines of what strmdr had stated regarding this stone as being more appropriate in a pendant setting.

I''ve read in other posts that HCA scores that are less than 0.6 or 0.5 as being not so good performers as opposed to 1.0 (My guess is that the difference would not be noticeable where performance is concerned. Or is there a difference??)
3.gif
 

strmrdr

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Date: 8/10/2005 4:13:15 PM
Author: CSI_guy
Thanks for the input belle and strmdr.


I understand the concept of anything under 2 on the HCA being great.


My question was more along the lines of what strmdr had stated regarding this stone as being more appropriate in a pendant setting.



I''ve read in other posts that HCA scores that are less than 0.6 or 0.5 as being not so good performers as opposed to 1.0 (My guess is that the difference would not be noticeable where performance is concerned. Or is there a difference??)
3.gif

It is still a strong performer and a stunning diamond.
Against pretty much most diamonds it would flat out blow them away but against a equally good diamond more tuned for ring use it would look slightly worse.
 

LadyluvsLuxury

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WOW strmrdr, thanks for linking that. Gives me something ELSE to look for! So is the only way to know if a stone would be lacking in performance in the mentioned lighting conditions through an ISee2?
Date: 8/10/2005 4:28:32 PM
Author: strmrdr
http://www.goodoldgold.com/0_815ct_d_si1_h%26a.htm

That diamond in the GOG learning section has simular construction and will explain more about what Im talking about.
 

belle

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Date: 8/10/2005 4:18:48 PM
Author: strmrdr

It is still a strong performer and a stunning diamond.
Against pretty much most diamonds it would flat out blow them away but against a equally good diamond more tuned for ring use it would look slightly worse.
i agree with strm about this being a stunning diamond. ...except the part about it looking ''worse''. you may (or may not) notice it looking a bit different, but i wouldn''t say it looks worse.
 

belle

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Date: 8/10/2005 4:44:09 PM
Author: LadyluvsLuxury
WOW strmrdr, thanks for linking that. Gives me something ELSE to look for! So is the only way to know if a stone would be lacking in performance in the mentioned lighting conditions through an ISee2?
no, that would be using a machine to split hairs in minute diamond charataristics that your eye probably won't be able to perceive anyway.
 

strmrdr

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Date: 8/10/2005 5:03:32 PM
Author: belle
Date: 8/10/2005 4:18:48 PM

Author: strmrdr


It is still a strong performer and a stunning diamond.

Against pretty much most diamonds it would flat out blow them away but against a equally good diamond more tuned for ring use it would look slightly worse.
i agree with strm about this being a stunning diamond. ...except the part about it looking ''worse''. you may (or may not) notice it looking a bit different, but i wouldn''t say it looks worse.


This is one of those that iv actualy been able to test is person and it is a visible difference.
 

strmrdr

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Date: 8/10/2005 4:44:09 PM
Author: LadyluvsLuxury
WOW strmrdr, thanks for linking that. Gives me something ELSE to look for! So is the only way to know if a stone would be lacking in performance in the mentioned lighting conditions through an ISee2?

Date: 8/10/2005 4:28:32 PM

Author: strmrdr

http://www.goodoldgold.com/0_815ct_d_si1_h%26a.htm


That diamond in the GOG learning section has simular construction and will explain more about what Im talking about.


few other ways:
1> Trusted vendor looking over the diamond.
2> general rule of thumb is that if 34.x and 40.y that if y > x by more than .1 to .2 it might be an issue. But if the P angle is below 40.75 it may be more of an issue. More data is need on that.
3> .gem file using the Gem Advisor software using the office lighting setting.
4> diamcalc
5> side by side comparison in person is of course best.
 

belle

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Date: 8/10/2005 5:59:19 PM
Author: strmrdr

Date: 8/10/2005 5:03:32 PM
Author: belle

Date: 8/10/2005 4:18:48 PM

Author: strmrdr


It is still a strong performer and a stunning diamond.

Against pretty much most diamonds it would flat out blow them away but against a equally good diamond more tuned for ring use it would look slightly worse.
i agree with strm about this being a stunning diamond. ...except the part about it looking ''worse''. you may (or may not) notice it looking a bit different, but i wouldn''t say it looks worse.


This is one of those that iv actualy been able to test is person and it is a visible difference.
i do not doubt that you were able to see a visible difference strm. i''m saying that not everyone would be able to perceive the difference and i certainly wouldn''t say it was ''worse''. just different. beauty is in the eye of the beholder.
 

strmrdr

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Here is what Gem Advisor shows.
First the learning stone from GOG that he rejected.

gogexamplebad.jpg
 

strmrdr

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c: 34.1 P 40.9 The 34.1 is a little shallower than my favorites but its in the good zone.

gogexamplegood.jpg
 

strmrdr

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Notice how much more dull and dingy the first one looks compared to the second?
While gem advisor isnt the last word for this kind of thing it does show the difference.
 

belle

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Date: 8/10/2005 6:08:01 PM
Author: strmrdr

Date: 8/10/2005 4:44:09 PM
Author: LadyluvsLuxury
WOW strmrdr, thanks for linking that. Gives me something ELSE to look for! So is the only way to know if a stone would be lacking in performance in the mentioned lighting conditions through an ISee2?


Date: 8/10/2005 4:28:32 PM

Author: strmrdr

http://www.goodoldgold.com/0_815ct_d_si1_h%26a.htm


That diamond in the GOG learning section has simular construction and will explain more about what Im talking about.


few other ways:
1> Trusted vendor looking over the diamond.
2> general rule of thumb is that if 34.x and 40.y that if y > x by more than .1 to .2 it might be an issue. But if the P angle is below 40.75 it may be more of an issue. More data is need on that.
3> .gem file using the Gem Advisor software using the office lighting setting.
4> diamcalc
5> side by side comparison in person is of course best.
1. agreed
2. okay, still would rather see the idealscope. especially since scan is within .2
3. would rather see idealscope
4. idealscope here too since i understand patterning and minors are assumed in dc
5. of course. totallly agree.
 

strmrdr

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Date: 8/10/2005 6:26:14 PM
Author: belle
Date: 8/10/2005 6:08:01 PM

Author: strmrdr


Date: 8/10/2005 4:44:09 PM

Author: LadyluvsLuxury

WOW strmrdr, thanks for linking that. Gives me something ELSE to look for! So is the only way to know if a stone would be lacking in performance in the mentioned lighting conditions through an ISee2?



Date: 8/10/2005 4:28:32 PM


Author: strmrdr


http://www.goodoldgold.com/0_815ct_d_si1_h%26a.htm



That diamond in the GOG learning section has simular construction and will explain more about what Im talking about.



few other ways:

1> Trusted vendor looking over the diamond.

2> general rule of thumb is that if 34.x and 40.y that if y > x by more than .1 to .2 it might be an issue. But if the P angle is below 40.75 it may be more of an issue. More data is need on that.

3> .gem file using the Gem Advisor software using the office lighting setting.

4> diamcalc

5> side by side comparison in person is of course best.
1. agreed

2. okay, still would rather see the idealscope. especially since scan is within .2

3. would rather see idealscope

4. idealscope here too since i understand patterning and minors are assumed in dc

5. of course. totallly agree.


ideal-scope/lightscope images have next to nothing to do with showing how a diamond looks in indirect light.
Look at the lightscope photo for the gog learning diamond above.
 

belle

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gogexamplebad.jpg
gogexamplegood.jpg


hmmmmm... nice pictures but are those in gray trays, white or black? also, stereo or mono eye view? hehehehe
9.gif
9.gif
 

strmrdr

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Date: 8/10/2005 6:38:23 PM
Author: belle
gogexamplebad.jpg
gogexamplegood.jpg



hmmmmm... nice pictures but are those in gray trays, white or black? also, stereo or mono eye view? hehehehe
9.gif
9.gif
Rofl
 

belle

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Date: 8/10/2005 6:30:34 PM
Author: strmrdr


Date: 8/10/2005 6:26:14 PM
Author: belle


Date: 8/10/2005 6:08:01 PM

Author: strmrdr

few other ways:

1> Trusted vendor looking over the diamond.

2> general rule of thumb is that if 34.x and 40.y that if y > x by more than .1 to .2 it might be an issue. But if the P angle is below 40.75 it may be more of an issue. More data is need on that.

3> .gem file using the Gem Advisor software using the office lighting setting.

4> diamcalc

5> side by side comparison in person is of course best.
1. agreed

2. okay, still would rather see the idealscope. especially since scan is within .2

3. would rather see idealscope

4. idealscope here too since i understand patterning and minors are assumed in dc

5. of course. totallly agree.


ideal-scope/lightscope images have next to nothing to do with showing how a diamond looks in indirect light.
Look at the lightscope photo for the gog learning diamond above.

you'd have to do a lot of convincing to make me think a computer view could actually tell me more than an idealscope or h&a image...even if the numbers were all perfectly perfect, i have not seen anything that leads me to believe that the lighting judgments in these computer programs are proven.

2.gif

 

belle

Super_Ideal_Rock
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hmmmmm......
well csi, i can''t reconcile those proportions. with that angle, depth and girdle combination the table would have to be larger than 56%are you sure on your numbers? (or maybe i''m not doing this right
37.gif
)
done playing for now...gotta run.

wireframe_1.JPG
 

EZ

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Messages
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Date: 8/10/2005 4:01:10 PM
Author: strmrdr
That combo would make a better pendant than a ring.
It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light.
On the good side of the coin it would probably tolerate dirt buildup better than some.
I am missing something here.
40.gif
Why would that combo make a better pendant than a ring? What indicates that "It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light" Is there something about the angles?

I am curious because I have a similar HCA score in a slightly smaller stone (1.012 ct, Thin to Medium Faceted, T: 55, D: 60.3, C: 34.7, P: 40.6, ID/ID.) Would it be better set in a pandant than in a ring?

CSexample.jpg
 

strmrdr

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Date: 8/10/2005 7:43:17 PM
Author: EZ
Date: 8/10/2005 4:01:10 PM

Author: strmrdr

That combo would make a better pendant than a ring.

It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light.

On the good side of the coin it would probably tolerate dirt buildup better than some.

I am missing something here.
40.gif
Why would that combo make a better pendant than a ring? What indicates that ''It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light'' Is there something about the angles?


I am curious because I have a similar HCA score in a slightly smaller stone (1.012 ct, Thin to Medium Faceted, T: 55, D: 60.3, C: 34.7, P: 40.6, ID/ID.) Would it be better set in a pandant than in a ring?

Its the relationship of the angles to one another.
shallow/shallow and steep/shallow are the problem childs.
Yours doesnt fall into either catagory.
It would work well in either.
 

strmrdr

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Date: 8/10/2005 7:27:05 PM
Author: belle
Date: 8/10/2005 6:30:34 PM

Author: strmrdr



Date: 8/10/2005 6:26:14 PM

Author: belle



Date: 8/10/2005 6:08:01 PM


Author: strmrdr


few other ways:


1> Trusted vendor looking over the diamond.


2> general rule of thumb is that if 34.x and 40.y that if y > x by more than .1 to .2 it might be an issue. But if the P angle is below 40.75 it may be more of an issue. More data is need on that.


3> .gem file using the Gem Advisor software using the office lighting setting.


4> diamcalc


5> side by side comparison in person is of course best.
1. agreed


2. okay, still would rather see the idealscope. especially since scan is within .2


3. would rather see idealscope


4. idealscope here too since i understand patterning and minors are assumed in dc


5. of course. totallly agree.



ideal-scope/lightscope images have next to nothing to do with showing how a diamond looks in indirect light.

Look at the lightscope photo for the gog learning diamond above.


you'd have to do a lot of convincing to make me think a computer view could actually tell me more than an idealscope or h&a image...even if the numbers were all perfectly perfect, i have not seen anything that leads me to believe that the lighting judgments in these computer programs are proven.

2.gif



If it wasnt confirmed by other means I wouldnt just go by the computer generated images.
In this case it agrees with what is seen using other means and im using them in an attempt to explain it.
 

Demelza

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Date: 8/10/2005 4:01:10 PM
Author: strmrdr
That combo would make a better pendant than a ring.

It lacks contrast in the viewing conditions and the lighting envirement of a ring in indirect light.

On the good side of the coin it would probably tolerate dirt buildup better than some.

Having been through an agonizing decision regarding a stone with a similar HCA score, I think it might be a little misleading to say that these stones would necessarily be better in a pendant. I think Belle is right that there are many, many people who would not be able to tell the difference between tenths of a degree. I certainly can't. Having compared my new stone with several others, I concluded that it is just as good a light performer as those with "better" angles. Mind you, these were all ideal cuts, so we're not talking about just any stones. I think that it's important to remember that there are a lot of different relationships between crown and pavilion that will produce a beautiful stone. If the stone looks like it might work in other ways (i.e. color, clarity, size, price) there is no reason not to take a look at it to see what your eyes see. You may love it, you may not -- but don't stress (like I did) about minute differences without first seeing what your own preferences are.

ETA: The diamond from which I'm upgrading had almost identical specs to the one you're considering and it was a stunner! Crown angle was 34.9 and pavilion angle was 40.7.
 

EZ

Rough_Rock
Joined
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Thanks! Is there a cheat sheet on the angles for these problem childs? I am trying to grasp the concepts here but finding that some simple rote memorization tricks are a good crutch for now.


I am guessing that the subject diamond's 34.9 crown tips it into the Steep/shallow category and my 34.7 makes it an okay/shallow cut? They both have a 40.6 paviliion. The subject's crown/pavilion ratio is .8596 (v .8547). Does that ratio have anything to do with it.

Again, I am grasping here. I have tried to follow some of the recent threads on this but think I may need to gobackto basics for a while.

BTW: This is the subject Diamond's HCA with mine superimposed in black. That little a shift makes a difference?
I know - this is be splitting hairs! It was already stated the the subject diamond, when set in a ring, would blow away most maul store diamonds and I am sure that is true.

CSexample1.jpg
 

Rhino

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Funny... I sat down last night and had typed a resonse to this thread but then decided to withdraw. I''m not for causing heated discussions on stones from the competition but since an example of ours was posted for a comparison I thought I should comment.

You have a set of numbers here that fall in a tricky zone which borders on the fringes for our personal selection criteria. Whenever I see pavilion angles falling at or below 40.7 I proceed in testing with more caution as there are many *ideal* crown angle combinations which do not work as well, particularly in ambient/office type lighting conditions which is what Isee2 is testing in.

Strm is correct in pointing out that not many devices are sophisticated enough to detect these differences. Not Idealscope images, not HCA, not BrillianecScope either in most circumstances. Isee2 and Gem Advisor are perhaps the best indicators.

Interestingly GIA concurs with my findings on this as well and while the new GIA Cut system is rather loose when it comes to the steep/deep combo''s, in some of the circumstances I''m finding and testing they are in agreement with our assessment of shallow combos. Below are the upcoming GIA results on this particular combo which would also raise a red flag.

Now let me also say this ... of stones that get a GIA "very good" rating this is perhaps one of the nicest stones you''ll find in that category and its optical symmetry looks superb. In the case with the .815ct that was posted my staff could see the differences in office lighting which is what disqualified it from our buying decision.

As strm said ... there''s MUCH WORSE out there and if you never compare it to a stone that scores 9.0 and over on the Isee2 she may never see or know the differences for herself.

Good luck!

csegia.gif
 

Rhino

Ideal_Rock
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Also one correction Strm.

The view that most accurately demonstrates this phenomena within DiamCalc is the "Jewelry Store Lighting" view. The "office lighting" view which you and belle have posted doesn''t quite do it as effectively although differences can be noted there. Here''s a graphic of a top performer (left) next to that .815ct we had rejected (right). In this jewelry store lighting graphic you can easily see the darkening of the pavilion mains. When we had the stone in house we could see it was darker under the table as compared to stones with Isee2 scores of 9.0 and higher.

brightdarkmains.gif
 

belle

Super_Ideal_Rock
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rhino and strm,
i applaud
36.gif
your efforts in trying to explain this and find it interesting, as i like playing with these programs too…BUT i have to say that i don’t think you can use a 2-d caricature (haven't seen a diamond look like that!
37.gif
) to split hairs and determine differences in the performance of a diamond you've never even seen. the hca score already designates it as a winner (better than 95% of all diamonds on the market) but more importantly, the idealscope image looks great
3.gif

besides there is the possibility that the diamond in this thread could be a 34.7 crown angle and 40.8 pavilion angle…who knows if the sarin is right?
33.gif


sorry boys, i am just one of those kinda girls who doesn’t think the fake ones are as good as the real thing.
31.gif
 

strmrdr

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Date: 8/11/2005 6:32:29 PM
Author: belle
rhino and strm,

i applaud
36.gif
your efforts in trying to explain this and find it interesting, as i like playing with these programs too…BUT i have to say that i don’t think you can use a 2-d caricature (haven't seen a diamond look like that!
37.gif
) to split hairs and determine differences in the performance of a diamond you've never even seen. the hca score already designates it as a winner (better than 95% of all diamonds on the market) but more importantly, the idealscope image looks great
3.gif


besides there is the possibility that the diamond in this thread could be a 34.7 crown angle and 40.8 pavilion angle…who knows if the sarin is right?
33.gif



sorry boys, i am just one of those kinda girls who doesn’t think the fake ones are as good as the real thing.
31.gif

Belle,
Both Jon and myself have seen this with our own eyes in similar diamonds.
People split hairs all the time with the hca and ideal-scope images neither of which directly address indirect light performance.
The hca can give you a clue to look into it further but doesn’t provide the whole answer.
Just like we on PS have been separating for the best direct light performance we can also weed out those that have problems in indirect light.
Its no different than rejecting a diamond that has too much white on the ideal-scope image
I am using the computer generated images to show what im talking about.
If you ever happen to be close to Jon's store sometime Im sure he would be happy to demo it for you using real diamonds.
 
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