The Ideal numbers within Ideal cut (RB)

[diamondseeker2006]

What would be examples of some of the best number combinations (table, depth, crown angle, pavilion angle) to get ex, ex, ex, ex on the HCA and AGS0?

 

[pricescope]

White line is just for AGS0 CANDIDATES

Table 53%

Table 54%

Table 55%

Table 56%

Table 57%

Table 58%

Table 59%

Table 60%

Table 61%

 

[belle]

you can start with the default numbers in hca and just change them each a few degrees to find different combinations that work. ags0 candidates will fall within the solid white outlined box. you won't find too many ags0's with pavilion angles above 41, so when inputting numbers, keep the pa around 40.4-40.8 and the crown angle between 34-36.
have fun!

eta: or just look at the charts above! very handy!

thanks leonid.

 

[strmrdr]

By holding to ex, ex, ex, ex on the hca your reading too much into it.
pretty much anything between 1 and 2 is kicken in my book and down to .6 can be kicken too with the proper combo but they need to be checked.

The hca doesn''t take all the facets into account which can change the personality of the diamond and make the specific ratings meaningless.
The hca is best at predicting that the average crown angle works well with the average pavilion angle of the diamond.
Beyond that IS and ASET and other scope images come into play as the next step.

 

[diamondseeker2006]

Thanks Pricescope and Belle! This is very helpful.

Storm, the stone I am looking at falls in the AGS0 range on the HCA chart and has a 1.4 HCA. But the spread is VG. I am assuming that must be due to the depth being 62.

Is table size just a personal preference within 53-61? I am looking at 54 and it looks really small to me, but that is likely due to my current diamond having a large table.

 

[Rod]

Date: 5/12/2006 11:09:38 AM
Author: diamondseeker2006
Thanks Pricescope and Belle! This is very helpful.

Storm, the stone I am looking at falls in the AGS0 range on the HCA chart and has a 1.4 HCA. But the spread is VG. I am assuming that must be due to the depth being 62.

Is table size just a personal preference within 53-61? I am looking at 54 and it looks really small to me, but that is likely due to my current diamond having a large table.

Many prefer smaller tables, but the it can be very personal. My preference is for larger tables. Maybe that''s because my pet rock has a 59% table and it''s really stunning, plus it scores 1.2 on the HCA.

The reason the stone you''re commenting on apprears small is it''s steep/deep stone. That means more of the diamond is in it''s depth, which can make it appear smaller for its carat weight. That''s not bad depending on how you set such a stone, but if you bury the stone in a bezel setting for example, you can pay for weight you won''t see.

Good luck.........

 

[dragongem]

Question on the HCA, anything under 1 needs to be checked out then? Based on the cut advisor for this diamond it is .5 Does that mean it I should get it checked out?

http://www.goodoldgold.com/diamond/705/

thks!

 

[Mara]

actually, it''s not uncommon for the typical AGS0 ideals we see on here to have VG spread and not EX. only about 1 in 5 that i run through HCA typically have EX on spread. i would estimate that a more shallow depth but with other angles and specs aligned correctly would yield the most elusive 4 EX''s. Greg''s small ACA had 4 EX''s and i was like WOW that''s sweet...but i wouldn''t let that VG be a deal breaker on spread, esp if the score is not even close to 2.

 

[oldminer]

If you look over the AGA Cut Class charts you will see the 1A and 1B categories of "Ideal". Even 1B is inside the AGS 0 parameters and eliminates the worst cut of the AGS 0 stones. Even the worst of the AGS0 stones are not dogs, but the best ones do look a lot nicer.

Diamonds within the 1A cut are all excellent in appearance with no compromises. 1A is a tight category and difficult to find stones cut like that. It was not a commercial exercise when I made up these charts. If a commercial effort was made, the 1A would have been as wide as the current 1B and the old 1B would have been opened up as wide as the existing 2A. It might have been more widely accepted, but less honest in its approach to cut.

 

[diamondseeker2006]

David, I think it would be great to put a link to that AGS chart you mentioned on this thread. I am not sure where it is. Would you please post it? Thanks!

 

[JulieN]

Diamondseeker, the AGA cut chart is here: http://diamonds.pricescope.com/round.asp

The AGS cut chart(s) were posted at the beginning of the thread.

 

[strmrdr]

Date: 5/12/2006 12:50:07 PM
Author: dragongem
Question on the HCA, anything under 1 needs to be checked out then? Based on the cut advisor for this diamond it is .5 Does that mean it I should get it checked out?


http://www.goodoldgold.com/diamond/705/


thks!

yep
it should be pre-screened but ask Tim or Jon to check it for any problems with the shallow pavilion.

 

[dragongem]

Date: 5/12/2006 4:50:50 PM
Author: strmrdr

Date: 5/12/2006 12:50:07 PM
Author: dragongem

Question on the HCA, anything under 1 needs to be checked out then? Based on the cut advisor for this diamond it is .5 Does that mean it I should get it checked out?


http://www.goodoldgold.com/diamond/705/



thks!

yep
it should be pre-screened but ask Tim or Jon to check it for any problems with the shallow pavilion.

What would a shallow pavilion imply?

 

[diamondseeker2006]

Just out of curiosity, I just ran 6 or 8 diamonds from 2 vendors through the HCA and none had all Ex''s. And that included a couple of ACA''s. So I am now understanding that even ACA does not mean all excellents.

 

[strmrdr]

Date: 5/12/2006 7:19:37 PM
Author: dragongem

Date: 5/12/2006 4:50:50 PM

Author: strmrdr

Date: 5/12/2006 12:50:07 PM

Author: dragongem


Question on the HCA, anything under 1 needs to be checked out then? Based on the cut advisor for this diamond it is .5 Does that mean it I should get it checked out?



http://www.goodoldgold.com/diamond/705/




thks!

yep

it should be pre-screened but ask Tim or Jon to check it for any problems with the shallow pavilion.

What would a shallow pavilion imply?

darkness when viewed up close.
Its actualy better for a pendant or earrings but can in some cases be a problem in rings.
The problem is that the numbers cant tell you for sure if there is a problem or not. The numbers can just tell you to have it checked.

 

[Carlotta]

You could ask them to compare it to this one (slightly bigger/slightly different pavillion angle):

www.goodoldgold.com/diamond/1936

 

[dragongem]

Wow by this rate I will never find my perfect cut cut stone. *sigh*

http://www.goodoldgold.com/diamond/1567 1.5 on the HCA

http://www.goodoldgold.com/diamond/705 .8 on the HCA

So is choice 1 better than choice 2 then? and is higher white light return better than higher scintillation?

 

[Carlotta]

Date: 5/12/2006 8:38:40 PM
Author: Carlotta
You could ask them to compare it to this one (slightly bigger/slightly different pavillion angle):

www.goodoldgold.com/diamond/1936

check out the Gemex report on this one!! Has 1.2 on HCA...........
It''s a VS2, but check out the clarity plot

 

[JulieN]

Date: 5/12/2006 8:39:09 PM
Author: dragongem
Wow by this rate I will never find my perfect cut cut stone. *sigh*

http://www.goodoldgold.com/diamond/1567 1.5 on the HCA

http://www.goodoldgold.com/diamond/705 .8 on the HCA

So is choice 1 better than choice 2 then? and is higher white light return better than higher scintillation?

Total thread jack...

the F VS1 has already been checked for this darkness that strmrdr is talking about. and at a pav. angle of 40.6 it''s not that shallow. call gog and ask them to talk to you about each one.

 

[dragongem]

Date: 5/12/2006 8:47:11 PM
Author: Carlotta

Date: 5/12/2006 8:38:40 PM
Author: Carlotta
You could ask them to compare it to this one (slightly bigger/slightly different pavillion angle):

www.goodoldgold.com/diamond/1936

check out the Gemex report on this one!! Has 1.2 on HCA...........
It''s a VS2, but check out the clarity plot

I''ve been advised not to go below a VS1 but this diamond does look beautiful. Should I''d be concerned about the thin girdle?

 

[JulieN]

no.

edit: that is, thin girdle is fine. and unless you have a "mind-clean" thing about VS1 clarity, oftentimes you will never be able to see things in a VS2.

 

[dragongem]

So given this new option which would you choose? 705 or 1936?
It is so hard to decide based on #s....

 

[JulieN]

I don''t think you''ll ever notice that pinpoint...

The VS2 looks scrumptious!

 

[dragongem]

Thanks Julie, OMG I sure hope my diamond search can come to an end finally....

 

[Carlotta]

Call GOG and ask them to compare them re: clarity and overall look......or they might suggest another option!!

Good luck!!!

 

[strmrdr]

Date: 5/13/2006 2:03:55 AM
Author: Carlotta
Call GOG and ask them to compare them re: clarity and overall look......or they might suggest another option!!


Good luck!!!

Yep thats your best bet.

 

[diamondseeker2006]

That stone does look beautiful, but I agree with having Jonathan looking at both. The VS1 or 2 issue I think is a mind-clean issue. I am wrestling with the same thing. I am looking at an H VS2 right now, and the inclusions are near the edge and very insignificant under 10x magnification. I am really okay with that, but would I rather have a VS1? I think the answer for me is, yes. But would anyone in the world besides me ever know the difference? No. These hearts and arrows stones are the most beautiful dimaonds I have ever seen.

 

[Sundial]

DS2006 are you going to post pictures for us of your Dimend Scaasi ring? You know the numbers are really just fine on that stone and as you've already noted very few diamonds get all excellents on the HCA. My Hearts on Fire center stone rated a 1.5 and got all excellents except for a very good on spread. I'm not sure that a diamond with all excellents would look any prettier anyway. However when all is said and done you need to find a diamond you are thrilled with and they can have different personalities.

 

[diamondseeker2006]

Sundial, after entering several WF ACA's and some GOG's into the HCA, I found none that got all excellents. So I am completely over the need to find that! If a stone is good enough for the ACA label, it is probably more than good enough for me. And, this stone from Dimend Scassi had as good a score as any of theirs. I realize it is an excellent stone in a very desirable size. I really can't imagine a stone being much more beautiful. However....I am used to an F, and I am just not sure I'd be happy in the long run with an H. I think a G might be the answer to whiter color but at a better price than for F (I know you have F, you lucky girl!). I think I am going to aim for a G VS1 at 1.33 to 1.4, with a diameter of close to 7.1 or better. I realize that may mean I have to wait to find the right stone (nobody seems to have one at the moment), but I think it will be worth it in the long run. Now that I have seen the beauty of a well cut H&A stone, that's what I want. But I need the color and clarity to be perfect for me, too, as I do not plan to ever upgrade it!

(Let me add that I am not making a final decision on returning this one before I go to Tiffany's next Saturday so I can compare the size and color with other nice quality diamonds.)

Forgot to add, I'll try to get pictures when my husband gets home from work. We have a wedding at 3:00. If not today, then I'll try tomorrow.

 

[Sundial]

I understand completely and you will want to take your time and find just the right diamond! I would still love to see pictures of your ring when you get a chance.