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Question for Mr. Gary Holloway

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JA72

Rough_Rock
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Jan 16, 2009
Messages
46
Hello Mr. Holloway,

I started another string earlier but I am hoping to contact you via the forums with a question about the HCA calculator and the tendency for it to round up the table percentage on the results page. I will paste my original post. I wonder if the .5% makes much of a difference . Also, I would like to know what you think of the diamond below. I think I have ruled it out after talking to the more experienced members of the forum, but I would also like to know your opinion of this diamond since the HCA rates it a .9. Please see the original post below:

Hi,

I inputted the specs into the HCA calculator of a diamond I am interested in. When I hit submit, it changes the table % rounding it up. I would like to know what everyone thinks of this diamond and any areas of concern you may have after seeing the specs. Also, I would like to know how the girdle will affect the performance of this diamond since it varies greatly from thin to thick. Will this girdle affect the HCA rate? I am guessing not since the girdle is not factored into the HCA calculator. Thanks :)


1.32ct
7.17 x 7.18 x 4.27mm
Ideal cut
F (VVS2)
Ex polish
Ex symmetry
Fl - none
AGS 000
Table 58.5
Depth 59.5
Crown angle 32.6
Pavillion angle 41.0
Girdle (faceted) 1.0-3.1% (will the thin part of this girdle be of concern when setting it?)
Culet Pointed

Please let me know how you think this will perform and if there are any areas that are not so great.
Thank you in advance for your time.


 

Stone-cold11

Super_Ideal_Rock
Joined
Sep 9, 2008
Messages
14,069
The graph of the HCA is only done in an increment of 1% for table size. At 59.5% of course it is rounded up to 60% table, standard math practice, what do you mean by tendencies to round up? At 59.4%, the score is ploted on a 59% table, round down.
 

Lorelei

Super_Ideal_Rock
Premium
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Messages
42,064
Date: 4/7/2009 12:16:09 PM
Author:JA72




Hello Mr. Holloway,

Garry Holloway should be along later JA and can give you the information you need in great detail as you know he created the HCA and is indeed the best person to help you with any queries concerning it. He is in Australia so he should be around in a while and be able to help you
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
I was speaking specifically about the diamond I posted. It rounded up from 58.5 on the AGSL report to 59. To see if it was a fluke I ran another diamond with the following details :

55.8 Table
61.4 Depth
34.4 Cr
40.7 Pv

The results page actually rounded down this time to a 55 table. So, standard math rules don''t apply in all cases. Maybe .8% doesn''t make a difference in the final results which is why I was asking Mr. Holloway. It could be a programming glitchm (probably not) but in case it is, maybe he would want to know. Either way, I just wanted to find out from the Zen master since I am relatively new to the diamond world and want to make sure I don''t spend 11-14k diamond unseen without researching as much as possible. I know that Mr. Holloways HCA is a valuable tool in eliminating poor performers and want to make sure this rounding up (maybe down) will not drastically change the HCA score.
 

JA72

Rough_Rock
Joined
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Messages
46
Thanks Lorelei :) You are always so helpful! I hope Mr. Holloway checks the forums on a regular basis
 

Lorelei

Super_Ideal_Rock
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Date: 4/7/2009 3:35:55 PM
Author: JA72
Thanks Lorelei :) You are always so helpful! I hope Mr. Holloway checks the forums on a regular basis
Most welcome! Garry is around and I ' spoke' to him this morning in fact, so he could well be here later and should see this when he logs in.
 

Stone-cold11

Super_Ideal_Rock
Joined
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Messages
14,069
Date: 4/7/2009 3:34:51 PM
Author: JA72
I was speaking specifically about the diamond I posted. It rounded up from 58.5 on the AGSL report to 59. To see if it was a fluke I ran another diamond with the following details :

55.8 Table
61.4 Depth
34.4 Cr
40.7 Pv

The results page actually rounded down this time to a 55 table. So, standard math rules don't apply in all cases. Maybe .8% doesn't make a difference in the final results which is why I was asking Mr. Holloway. It could be a programming glitchm (probably not) but in case it is, maybe he would want to know. Either way, I just wanted to find out from the Zen master since I am relatively new to the diamond world and want to make sure I don't spend 11-14k diamond unseen without researching as much as possible. I know that Mr. Holloways HCA is a valuable tool in eliminating poor performers and want to make sure this rounding up (maybe down) will not drastically change the HCA score.
Hmm... didn't happen to me when I input these numbers. I still got the 56% table plot which is inline with the rounding to whole numbers.
 

Stone-cold11

Super_Ideal_Rock
Joined
Sep 9, 2008
Messages
14,069
Date: 4/7/2009 3:34:51 PM
Author: JA72
I was speaking specifically about the diamond I posted. It rounded up from 58.5 on the AGSL report to 59. To see if it was a fluke I ran another diamond with the following details :

55.8 Table
61.4 Depth
34.4 Cr
40.7 Pv

The results page actually rounded down this time to a 55 table. So, standard math rules don''t apply in all cases. Maybe .8% doesn''t make a difference in the final results which is why I was asking Mr. Holloway. It could be a programming glitchm (probably not) but in case it is, maybe he would want to know. Either way, I just wanted to find out from the Zen master since I am relatively new to the diamond world and want to make sure I don''t spend 11-14k diamond unseen without researching as much as possible. I know that Mr. Holloways HCA is a valuable tool in eliminating poor performers and want to make sure this rounding up (maybe down) will not drastically change the HCA score.
Didn''t get that, I did a screen capture of my HCA output this time.

stonecold04082009.JPG
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
Very odd! HMMM.... here is my screen shot where it rounded the table down from 55.8 to 55 (see below). I will try on firefox, maybe that will make a difference??? Either way, it didn''t make a difference in the HCA score. It still shows as a .09 when rounded down.

I pasted both screen shots into a word document, but it is too large to attach (430KB). I am not sure how to resize it to attach and a standard paste doesn''t come through as yours did. Oh well. If you want me to email it to you, I can do that....
 

Lorelei

Super_Ideal_Rock
Premium
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Messages
42,064
Date: 4/9/2009 6:17:50 AM
Author: JA72






Very odd! HMMM.... here is my screen shot where it rounded the table down from 55.8 to 55 (see below). I will try on firefox, maybe that will make a difference??? Either way, it didn't make a difference in the HCA score. It still shows as a .09 when rounded down.

I pasted both screen shots into a word document, but it is too large to attach (430KB). I am not sure how to resize it to attach and a standard paste doesn't come through as yours did. Oh well. If you want me to email it to you, I can do that....
You can't email or contact consumer posters here JA.

Hang tight, Garry should be along soon and will give you the info you need as you specifically requested his advice! There won't be a question concerning his HCA that he can't answer. I will keep an eye out for him for you so he sees this.
 

Stone-cold11

Super_Ideal_Rock
Joined
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Messages
14,069
Too weird... I am doing these on Firefox, btw.

just post as 2 separate pics. Should be small enough that way.
 

Lorelei

Super_Ideal_Rock
Premium
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Messages
42,064
Date: 4/9/2009 10:35:44 AM
Author: JA72
Oops ;-) Newbie mistake, thanks for letting me know.
No problem! Hang in there, Garry will get to this thread I am sure!
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
I''m sure he is really busy or maybe on vacation in that beautiful part of the world. I would love his input on the diamond and the HCA question but I understand if the timing just isn''t right.

Thanks again Lorelei and Stone-cold :)
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
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Messages
15,657
Date: 4/7/2009 12:16:09 PM
Author:JA72

Hello Mr. Holloway,

I started another string earlier but I am hoping to contact you via the forums with a question about the HCA calculator and the tendency for it to round up the table percentage on the results page. I will paste my original post. I wonder if the .5% makes much of a difference . Also, I would like to know what you think of the diamond below. I think I have ruled it out after talking to the more experienced members of the forum, but I would also like to know your opinion of this diamond since the HCA rates it a .9. Please see the original post below:

Hi,

I inputted the specs into the HCA calculator of a diamond I am interested in. When I hit submit, it changes the table % rounding it up. I would like to know what everyone thinks of this diamond and any areas of concern you may have after seeing the specs. Also, I would like to know how the girdle will affect the performance of this diamond since it varies greatly from thin to thick. Will this girdle affect the HCA rate? I am guessing not since the girdle is not factored into the HCA calculator. Thanks :)



1.32ct
7.17 x 7.18 x 4.27mm
Ideal cut
F (VVS2)
Ex polish
Ex symmetry
Fl - none
AGS 000

Table 58.5
Depth 59.5
Crown angle 32.6
Pavillion angle 41.0
Girdle (faceted) 1.0-3.1% (will the thin part of this girdle be of concern when setting it?)
Culet Pointed

Please let me know how you think this will perform and if there are any areas that are not so great.

Thank you in advance for your time.



Firstly the charts has no bearing on the HCA results.
Secondly table size has about the least effect on beauty of the 3 main variables.

The girdle could indicate the stone has poor symmetry.
What grading report does it have ? (AGS000 it is not for sure because it has Ex Ex symmetry - so the vendor is stoopid or a could be a cheat)

If it has poor symmetry (likely from the data then I would avoid the stone because parts will be very dark under close inspection.

HCA IS A REJECT TOOL. PLEASE DONT USE IT AS A SELECTION TOOL
 

Lorelei

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
42,064
Date: 4/10/2009 7:55:19 AM
Author: JA72
I'm sure he is really busy or maybe on vacation in that beautiful part of the world. I would love his input on the diamond and the HCA question but I understand if the timing just isn't right.

Thanks again Lorelei and Stone-cold :)
ETA - there he is!
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
Mr. Holloway,

Thank you for the reply. The report is AGSL here is the link. http://www.bluenile.com/round-diamond-1-carat-ideal-cut-f-color-vvs2-clarity_LD01118119#grading_report. Definitely don''t want a stone with dark areas. OH this is all so confusing. Thought AGSL was the most reputable of all graders and when I found one with such high marks by AGSL, I thought I found the one.

Looks like I am heading back to hunting. I think I might have to let it rest a few months before I throw my laptop out the window or develop permanent cross eyes.
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
Thanks :) It must be that I am losing my mind from looking at a zillion reports. I forgot that EX with GIA isn''t the same as with AGSL. Do you think the price is fair ?

When you said the stone should be fine, does that mean just average or that you think it is a great stone?

If you think the the price is fair in todays market and there won''t be black areas or danger with the girdle (1.0%-3.1%) with mounting in a setting, that we will buy it. After all they do have a good return policy if I don''t love it after seeing it in person.
 

John P

Ideal_Rock
Trade
Joined
May 1, 2008
Messages
3,563
Date: 4/10/2009 8:51:46 AM
Author: JA72
Thanks :) It must be that I am losing my mind from looking at a zillion reports. I forgot that EX with GIA isn''t the same as with AGSL. Do you think the price is fair ?

When you said the stone should be fine, does that mean just average or that you think it is a great stone?

If you think the the price is fair in todays market and there won''t be black areas or danger with the girdle (1.0%-3.1%) with mounting in a setting, that we will buy it. After all they do have a good return policy if I don''t love it after seeing it in person.
Average is relative. I''d predict it to be far better than the average found in mainstream markets like the mall. How does it measure against other AGS0s? Against cut-focused collections? Against other makes of RB? Impossible to tell without more information.

To cut-focused experts a grading report is (like HCA) simply a more advanced rejection tool. Those data points are only averages of many measurements. An Ideal-Scope photo (developed by Garry) or ASET image (developed by AGS) will show how the facets work together in 3D and reveal the level of cut precision, brillianteering details, variation from averages etc. The fact that it has the 0 in light performance is a great pedigree...this will be a pretty diamond, no doubt.

What do the basic numbers tell us? The table size and 41.0/32.6 average angles put it more towards a 60/60 make than the near-Tolkowskys we often see on PS. That also makes me want an ASET image, to see what kind of contrast pattern it has, since the lower crown height indicates there will be more brightness and less fire in its performance qualities.

No worries about the girdle thickness, by the way. BN has a glitch in its software that interprets AGS girdle measurements incorrectly. The new Platinum report from AGS will correct this, and they are extending the option to include a computer-generated ASET on that new report...while it''s not an actual image, kudos to AGS for that.
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
John you ROCK! Pun intended :)

I would love an IS and ASET image also but BN doesn''t have them available. I asked if they could GCAL,Sarin, ASET or IS it for me. I told them that I was willing to pay and agree that the images were non-refundable even if I returned the stone. They again said they don''t have those services. The stone will be put in a plain 6 prong WG setting (won''t ship loose) until I settle on the permanent setting (leaning towards a WF) once I commit to a stone after viewing it.

So, I am thinking of investing in the IS / ASET set for $199 online. I have always wanted one anyways. I saw on the website that I can use it on mounted diamonds and that I can also take pictures of the results. I don''t know how well the pictures will turn out since I am neither an experienced photographer or IS/ASET user.

I think it will be worth it since there is only a 30 day window for diamond returns at BN. I don''t know that I trust my naked eyes to determine if it is a great stone therefore the set would be a very useful tool.

I am not sure what the 60/60 you mentioned signifies. Is this not a good thing?
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
No worries about the girdle thickness, by the way. BN has a glitch in its software that interprets AGS girdle measurements incorrectly. The new Platinum report from AGS will correct this, and they are extending the option to include a computer-generated ASET on that new report...while it''s not an actual image, kudos to AGS for that.
Sorry, also forgot to ask about the girdle. I was worried when I saw on the report 1.0%-3.1% ( I think that is actually thin to thick) . I read on one of the links that thin girdles can chip by being bumped/hit or by the prongs during maintenance and setting. If this is any real possibility I don''t want to get this stone since I plan on keeping this one forever and not upgrading. I know, thats what all beginning diamond lovers say. Ill check back in a few years to see if my statement holds up :)
 

Lorelei

Super_Ideal_Rock
Premium
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Messages
42,064
Date: 4/10/2009 10:45:48 AM
Author: JA72



No worries about the girdle thickness, by the way. BN has a glitch in its software that interprets AGS girdle measurements incorrectly. The new Platinum report from AGS will correct this, and they are extending the option to include a computer-generated ASET on that new report...while it's not an actual image, kudos to AGS for that.
Sorry, also forgot to ask about the girdle. I was worried when I saw on the report 1.0%-3.1% ( I think that is actually thin to thick) . I read on one of the links that thin girdles can chip by being bumped/hit or by the prongs during maintenance and setting. If this is any real possibility I don't want to get this stone since I plan on keeping this one forever and not upgrading. I know, thats what all beginning diamond lovers say. Ill check back in a few years to see if my statement holds up :)
That translates to thin to medium and is well within desirable range. Rarely very thin can be a potential durability issue but not in all cases, sometimes the portion of the girdle which is very thin is only a small amount and not of any consequence - a trusted vendor will be able to advise with very thin girdles if there is cause for concern or not.

60 60 is a type of diamond which has a 60% depth and 60% table ( or close to). These can be good looking diamonds as long as in any case, the critical crown and pavilion angles are harmonious.
 

John P

Ideal_Rock
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Date: 4/10/2009 10:40:21 AM
Author: JA72
John you ROCK! Pun intended :)

I am not sure what the 60/60 you mentioned signifies. Is this not a good thing?
Thanks JA72. 60/60 is fine. It is a very common make of round brilliant, implying table and depth both close to 60%. These makes are beautiful with the right crown & pavilion combinations - just as any diamond can be.

In general terms the larger table of a 60/60 make implies a shallower crown height and less dispersion (fire) in the performance qualities - but with good angle pairings those stones have great white-brightness. Near-Tolkowsky makes have tables a bit smaller making for crown heights aound 15%. With good angle pairings (often specifically near 40.75/34.50) they are very balanced in fire and brightness. When you go smaller in table size and/or higher in crown height you begin to enter a rare area of high-crowned rounds with emphasis on fire in performance - possibly resembling antique, cushion or transitional cuts.

The info above is just a broad overview of 3 "makes" of RB. Other details come into play, especially lower halves, precise angle pairings and cut precision, and there are other possible makes.

One piece of advice: If possible, consider getting your diamond and setting from the same place. That way you''re covered in the rare event of chipping or damage during the setting process. If you do pursue separate avenues for them be sure to ask who will cover damage if it should occur (again, this is rare but good to be safe).
 

JA72

Rough_Rock
Joined
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Messages
46
Lorelei that link you sent sealed the sale for my own ASET / IS. Do you think I should take the ring to my local jeweler to have them remove the stone from the setting so that I can view it unobstructed with my ASET/IS when they both arrive. Come to think of it, they might not like that or do it for me since I didn''t buy the stone from them ....I will have to check with them in a few days to see if they will even do this for me. I wonder what the delivery time is to receive the scopes?

I think I will be ok with the stone being cut more for brilliance than fire as long as I get a good amount of fire. It doesn''t have to be completely on fire since I think I understand that to get one you have to sacrifice a little on the other. As long as there isn''t no fire/ very little fire I should be ok with that. You will see me chacing candelight, streetlights and visiting local pubs with it the first few days to see how it performs :) I am off to rest my eyes and find some excedrine!
 

JA72

Rough_Rock
Joined
Jan 16, 2009
Messages
46
Thanks again for being so informative John, Lorelei and the gang :). I wanted to do that, but BN has a pretty lousey (sorry BN)selection of settings. I have been pleased with the first diamond my husband gave me from BN when we were students 4 years ago. It is a signature ideal and I get compliments all the time on its brilliance and fire. But it is time to upgrade. I found a few great settings from WhiteFlash and they did tell me my options about sending the setting unset to me to have a local jeweler complete the setting. Another option was for me to send the stone to WF to complete the setting. However, I didn't think to ask about insurance. Thank GOD you told me about that. Would standard insurance (I plan to get a policy before I wear the ring out or have it worked on) cover damages in the rare event that it happens while being worked on?

Maybe all of this new information is telling me that I need to have everything lined up better and educate myself more before buying a stone/ setting. Lorelei has also given me a ton of links and information through out the past few week - KUDOS to Sensei Lorelei
Could be that the diamond dieties are telling me to keep looking and to educate myself more before committing..... Will sleep on it another day. My friend sent me an article telling me to wait because (was it NY times?) projected a 20-30% drop in diamond prices in the near future. OH the pressure!
 

Lorelei

Super_Ideal_Rock
Premium
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Messages
42,064
Date: 4/10/2009 11:03:20 AM
Author: JA72
Lorelei that link you sent sealed the sale for my own ASET / IS. Do you think I should take the ring to my local jeweler to have them remove the stone from the setting so that I can view it unobstructed with my ASET/IS when they both arrive. Come to think of it, they might not like that or do it for me since I didn''t buy the stone from them ....I will have to check with them in a few days to see if they will even do this for me. I wonder what the delivery time is to receive the scopes?

I think I will be ok with the stone being cut more for brilliance than fire as long as I get a good amount of fire. It doesn''t have to be completely on fire since I think I understand that to get one you have to sacrifice a little on the other. As long as there isn''t no fire/ very little fire I should be ok with that. You will see me chacing candelight, streetlights and visiting local pubs with it the first few days to see how it performs :) I am off to rest my eyes and find some excedrine!
Glad to help! I would think leave the stone set, you should be able to view it adequately with the tools whilst in the ring. And it sounds like you have the right idea in checking out the diamond in all types of lighting, that will give you a good idea of how it looks and behaves!
 
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